VIDEO - Israeli tanks, bulldozers and helicopters raided the Gaza Strip on Tuesday, killing the militant son of the territory's most powerful Hamas leader and 16 other Palestinians in one of the bloodiest days of fighting since the Islamic group took over the area in June.
Palestinian sniper fire across the border killed 20-year-old Carlos Andres Chavez, a volunteer from Quito, Ecuador, at the Ein Hashlosha kibbutz.
The killing of Hussam Zahar, 24, the son of hardline Hamas leader Mahmoud al-Zahar, and the civilian death in Israel threatened to fuel the violence even further at a time when Israel and moderate Palestinians in the West Bank are trying to move peacemaking into high gear.
At the morgue at Shifa Hospital, Mahmoud al-Zahar held his lifeless son's head in his hands and closed his eyes, then kissed him three times on the forehead and recited solemn verses from the Muslim holy book, the Quran.
Al-Zahar accused the moderate Palestinian president, Mahmoud Abbas of the rival Fatah movement, of complicity in his son's death.
"This is the hope of Abu Mazen and his colleagues, the collaborators with Israel and the spies of America," Zahar said, referring to Abbas by his nickname. Hamas, he vowed, will respond to Tuesday's raid "in the appropriate way. We will defend ourselves by all means."
Another al-Zahar son was killed in a botched Israeli assassination attempt against the elder al-Zahar in his home three years ago.
The killing of Hussam Zahar threatened to heat up Hamas' involvement in the daily barrage of rocket and mortar fire on southern Israel. While allowing other militant factions to attack southern Israeli communities with impunity, the Islamic militant group hasn't taken the lead on the assaults.
The operation Tuesday began when undercover Israeli troops moved several hundred yards into the territory to strike an abandoned house east of Gaza City that militants used for rocket-launching operations, Hamas said.
When Palestinian militants discovered the force, an exchange of fire erupted, the militants said. In the ensuing clashes, Israeli tanks fired at least three shells and aircraft struck twice in the area, Hamas said.
In all, 12 fighters and three civilians were killed by late morning, and more than 40 Palestinians were wounded, militants and doctors said. Shifa Hospital put out a radio call for blood donations because of the large number of wounded.
Deputy Defense Minister Matan Vilnai told Army Radio that "a large force of infantry and engineering corps troops, backed by tanks and the air force, is operating in the northern Gaza Strip."
The military spokesman's office said the clash was set off when militants approached the border fence, and troops opened fire.
Sniper attack on kibbutz volunteer
In the course of the fighting, a Palestinian sniper fired from the border area into Israel, killing 20-year-old Carlos Andres Chavez, a volunteer from Ecuador who was working in a potato field at the Ein Hashlosha kibbutz, Israeli officials said.
Hamas' military wing claimed responsibility.
"The shooting of the Ecuadorian youth demonstrates the necessity of the defensive measures the military is carrying out with pinpoint operations," Israeli military spokeswoman Maj. Avital Leibovich said.
Israel has been cracking down on Gaza militants who bombard southern Israel with rockets and mortars and attack troops along the border, even as it seeks peace with Abbas' West Bank-based government.
Broad Gaza offensive?
On Monday, Israeli Prime Minister Ehud Olmert suggested Israel would not launch a broad operation in Gaza, despite Defense Minister Ehud Barak's repeated assertions that a large-scale strike was inevitable, Abbas, who has controlled only the West Bank since Hamas overran Gaza, condemned the Israeli raid.
"We say to the world and Israel, that it is impossible to stay quiet about these crimes," He said. "It is impossible to bring peace under these circumstances."
Hamas' senior political leader, Ismail Haniyeh, denounced Abbas for trying to make peace with Israel.
"Shame, shame, for those who shake hands with the leaders of the occupation, those who sit with the occupation leaders, and those who give compromises to the occupation," Haniyeh told Hamas TV.
Threat to government coalition
While violence was swelling in Gaza, Olmert was struggling Tuesday to keep his coalition intact and broad enough to comfortably work toward reaching a peace deal with the moderate Palestinian government in the West Bank.
Hardline lawmaker Avigdor Lieberman is threatening to pull his 11-member Yisrael Beiteinu faction out of Olmert's government now that Israeli-Palestinian peace talks moved on Monday to the key issues in the conflict - final borders, disputed Jerusalem and the fate of Palestinian refugees.
Lieberman and the party will decide how to act after he meets with Olmert on Tuesday, Lieberman spokeswoman Irena Etinger said.
Ali Waked contributed to this report