A Qassam rocket fired from the northern Gaza Strip landed near a school in Sderot and another exploded in an open field, the police said.
An early warning system known as Red Dawn failed to sound a warning siren.
IDF Chief of Staff Lit-Gen Gadi Ashkenazi was touring the city at the time of the attack. "I came to hear and see what more we can do to help," Ashkenazi said after meeting Mayor Eli Moyal and residents of the city.
Hours later, two Qassam rockets were fired at the western Negev. One of the rockets landed on a road in Sderot, lightly injuring a resident. The other hit a house in the Eshkol town. No injuries were reported.
Residents of Sderot and the west Negev woke up to another day of Qassam attacks Friday morning as Hamas intensified its rocket fire at the city for the sixth day.
A rocket hit a Sderot gas station at around 9:30 am, lightly wounding one person. Two more people suffered shock. A second rocket hit a house in the town and caused structural damages.
The first salvo started shortly after 7 am, when Palestinians in north Gaza launched three rockets towards the Israeli community. The Color Red alert system sounded ahead of the attacks.
Two of the rockets landed in open areas on the Sapir College campus, and the third hit near Sderot's cemetery. No one was wounded and no damages were caused.
Roughly an hour after the first salvo, four more rockets were fired into the west Negev. Two landed south of Ashkelon, one landed in an open area near Sderot, and the fourth landed in an open area in the She'ar Hanegev Regional Council and caused a fire.
Shortly after the first series of attacks the Israeli Air Force retaliated with a missile strike on a Qassam cell in northern Gaza. Several members of the cell were hit.
Sderot Synagogue hit Thursday (Photo: Tsafrir Abayov)
Overnight Friday Israeli aircraft struck a building used by Hamas in northeast Gaza. Five Hamas members were killed in the strike. The IDF said that intelligence had indicated that a tunnel was being dug underneath the building towards Israeli territory.
Two members of Hamas' military wing were killed in an airstrike that targeted a car traveling in Gaza City early Friday evening, as the army stepped up attacks against the Islamic group. Hours later an airstrike targeted an empty Hamas school in the city.
About 30 rockets were fired at Sderot and western Negev communities on Thursday, and a total of about 90 rockets have been launched since Tuesday.
Palestinians fired a barrage around midnight Thursday at Sderot. One of the rockets hit a synagogue just minutes after the end of a celebration. Fortunately, most of the 300 people had already left the premises. Nonetheless, a number of people suffered from shock and the building was damaged.
Thursday evening politicians began arriving in Sderot to encourage the residents and to express solidarity with them. Prime Minister Ehud Olmert also arrived in the city and just before his departure heard the Color Red alert system warning of an impending attack. He was rushed by his bodyguards to one of the houses in the city.
In spite of the rocket barrages, most Sderot residents remained in the city. According to unofficial estimates, between 2,500 to 3,000 people (out of 23,000 residents) have left the southern town so far.