Israeli fighter jets bombed early Saturday the Hamas government headquarters in Gaza City. Palestinian sources said the four-storey building was completely destroyed. An IDF official said the building was apparently empty at the time of the attack. Egyptian Prime Minister Hisham Kandil met with senior Hamas figures in the building on Friday during his snap visit to Gaza. The building housed Hamas Prime Minister Ismail's office. Palestinian television released images of the destroyed building, which is located Gaza City's western sector. Following the attack Haniyeh tweeted: "The Zionists believe their attack will weaken us, but the opposite is true. It only strengthens our determination to liberate Palestine and increase deterrence in the face of the Zionist settler until we achieve victory." Related articles: Op-ed: The third front 'Attacks on 'Tel Aviv encourage Gazans' Protests held worldwide against IDF op Palestinian sources in Gaza said the IDF targeted a motorcyclist in the south Gaza town of Khan Younis. According to the report, one Palestinian was killed in the aerial strike. Palestinian sources further reported that one person was killed and three others were wounded in an IDF strike in Deir al-Balah. According to the report, another person was killed in an attack on a terror cell in Rafah's al-Sulan neighborhood. Since 6 pm Thursday the IDF attacked more than 200 terror targets in Gaza, including 120 rocket launchers and more than 20 smuggling tunnels in Rafah. On Saturday morning Israeli aircraft attacked a terror cell as it was preparing to launch rockets at Beersheba. Three terrorists were hit. In addition, the Air Force killed a Hamas officer who was in charge of the terror group's air defense The IDF attacked 830 terror targets in Gaza since Operation Pillar of Defense began. Destroyed Hamas building (Photo: EPA) Despite the aerial strikes in Gaza, more than 20 rockets hit south Israel early Saturday. There were no immediate reports of injury or damage. The rocket fire on Israel continued overnight, but there were no reports of injury or damage. The Color Red air raid siren was sounded in Netivot and the Ashkelon Beach Regional Council overnight, and sirens were activated again in Netivot and the Sdot Negev Regional Council at the break of dawn. Related articles: Protests held worldwide against IDF op Obama reiterates support for Israel 'Attacks on Tel Aviv encourage Gazans' Israel expanded its fierce air assault on rocket operations in the Gaza Strip on Saturday, striking Hamas government and security compounds, smuggling tunnels and electricity sources after an unprecedented rocket attack aimed at the holy city of Jerusalem raised the stakes in its violent confrontation with Palestinian terrorists. According to the Palestinians, one of the Israelis strikes targeted the Jabalia home of Ibrahim Salah, a senior Hamas Interior Ministry official. At least 20 people were injured in the strike, the sources said, adding that Israeli aircraft also attacked Hamas police headquarters. Israeli aircraft also kept pounding their initial targets, the terrorists' weapons-storage facilities and underground rocket-launching sites. The Israeli military called up thousands of reservists and massed troops, tanks and armored vehicles along the border with Gaza, signaling a ground invasion of the densely populated seaside strip could be imminent. Strike on building in Gaza Israel launched its military campaign Wednesday after days of heavy rocket fire from Gaza and has carried out some 700 airstrikes since, the military said. Terrorists, undaunted by the heavy damage the air attacks have inflicted, have unleashed some 500 rockets against the Jewish state, including new, longer-range weapons turned for the first time this week against Jerusalem and Israel's Tel Aviv heartland. Israel has slowly expanded its operation beyond military targets and before dawn on Saturday, the Gaza Interior Ministry reported, missiles smashed into two small Hamas security facilities as well as the massive Hamas police headquarters in Gaza City, setting off a huge blaze that engulfed nearby houses and civilian cars parked outside. No one was inside the buildings at the time. Rockets launched from Gaza, Saturday (Photo: EPA) In southern Gaza, Israeli aircraft went after the hundreds of underground tunnels militants used to smuggle in weapons and other contraband from Egypt, people in the area reported. A huge explosion in the area sent buildings shuddering in the Egyptian city of El-Arish, 30 miles (45 kilometers) away, an Associated Press correspondent there reported. The tunnels have also been a lifeline for residents of the area during the recent fighting, providing a conduit for food, fuel and other goods after supplies stopped coming in from Israel days before the military operation began. Missiles also knocked out five electricity transformers, plunging more than 400,000 people into darkness, according to the Gaza electricity distribution company. A separate airstrike leveled a mosque in central Gaza, damaging nearby houses, Gaza security officials and residents said. The military had no comment on that attack and it wasn't clear whether weapons or fighters were being harbored in the area. One person was killed and three dozen people were wounded in the various attacks, Gaza health official Ashraf al-Kidra said. In all, 30 Palestinians and three Israelis have been killed since the Israeli operation began. The Israeli military said it did not immediately have an accounting of its various overnight targets. "The Palestinian government emphasizes its steadfastness and support for the Palestinian resistance," government spokesman Ihab Hussein said in a text message to reporters after the wave of Israeli attacks. "It stands alongside its people, who are subject to this aggression." The widened scope of targets brings the two sides closer to the kind of all-out war they waged four years ago. Hamas, a terror group committed to Israel's destruction, was badly bruised during that confrontation, but has since restocked its arsenal with more and better weapons, and has been under pressure from smaller, more militant groups to prove its commitment to armed struggle against Israel. The attack aimed at Jerusalem on Friday and strikes on the Tel Aviv area twice this week dramatically showcased the terrorists' new capabilities, including a locally made rocket that appears to have taken Israeli defense officials by surprise. Both areas had remained outside the gunmen's reach in past rounds of fighting, and their use dramatically escalated the hostilities. IDF strike in Gaza, early Saturday (Video: Reuters) Just a few years ago, Palestinian rockets were limited to crude devices manufactured in Gaza. But in recent years, Israeli officials say, Hamas and other armed groups have smuggled in sophisticated, longer-range rockets from Iran and Libya, which has been flush with weapons since Moammar Gaddafi was ousted last year. The eerie wail of air raid sirens sounded in Jerusalem after the start of the Jewish Sabbath in the holy city, claimed by both Israel and the Palestinians as a capital and located about 75 kilometers (47 miles) from Gaza. Jerusalem residents were shocked to find themselves suddenly threatened by rocket fire, which, for more than a decade, had been limited to steadily broadening sections of southern Israel. The attack on the contested city was especially audacious, both for its symbolism and its distance from Gaza. Located roughly 50 miles (80 kilometers) from the Gaza border, Jerusalem had been considered beyond the range of Gaza rockets - and an unlikely target because it is home to the Al-Aqsa Mosque compound, Islam's third-holiest shrine. Most of the terrorists' rockets do not have guided systems, limiting their accuracy, though Israeli officials believe the terrorists' may have a small number of guided missiles that have not yet been used. Israeli police spokesman Micky Rosenfeld said the rocket landed in an open area southeast of the city - near the Palestinian city of Bethlehem and just a few miles from Al-Aqsa. Earlier on Friday, Gaza gunmen fired toward Tel Aviv for the second straight day, causing no injuries. "We are sending a short and simple message: There is no security for any Zionist on any single inch of Palestine and we plan more surprises," said Abu Obeida, a spokesman for Hamas' armed wing. Israeli leaders have threatened to widen the operation if the rocket fire doesn't halt. Foreign Minister Avigdor Lieberman said options included the possible assassination of Hamas' prime minister, Ismail Haniyeh, and other top leaders. "Every time that Hamas fires there will be a more and more severe response," he told Channel 2 TV on Friday. "I really recommend all the Hamas leadership in Gaza not to try us again. ... Nobody is immune there, not Haniyeh and not anybody else." Israeli Prime Minister Benjamin Netanyahu huddled with his emergency Cabinet on Friday night. Israeli media reported the meeting approved a request from Defense Minister Ehud Barak to draft 75,000 reservists. Earlier this week, the government approved a separate call-up of as many as 30,000 soldiers. Combined, it would be the biggest call-up of reserves in a decade. Lt. Col. Avital Leibovich, a military spokeswoman, said 16,000 reservists were called to duty on Friday and others could soon follow. She said no decision had been made on a ground offensive but all options are on the table. Dozens of armored vehicles have been moved to Israel's border with Gaza since fighting intensified Wednesday. The violence has widened the instability gripping the region, straining already frayed Israel-Egypt relations. The Islamist government in Cairo, linked like Hamas to the region-wide Muslim Brotherhood, recalled its ambassador in protest and dispatched Prime Minister Kandil to the territory on Friday to show solidarity. AP contributed to the report You can contact Elior Levy, Ynet's Palestinian Affairs Correspondent, at: paldesk@gmail.com Follow Ynetnews on Facebook and Twitter Receive Ynetnews updates directly to your desktop