Israeli warplanes on Thursday launched four simultaneous attacks in the Gaza Strip, residents and security sources said.

The targets included an abandoned building which used to be the headquarters of the Palestinian National Authority's intelligence department, a nearby sports hall and a neighboring training camp for the military wing of Islamic Hamas movement in northwest Gaza City. The F-16 fighter jets also struck a hill overlooking southeast Gaza City.

There has been no reports of casualties, since Hamas has evacuated all its security and military sites as violence flared since Saturday, when Hamas, which has controlled Gaza since 2007, fired more than 50 missiles and mortars towards Israeli army posts and Jewish communities near Gaza, ending a shaky ceasefire that had held for two years.

Earlier Thursday, Palestinian militants fired several rockets towards Israel, including Russian-made Grad missiles. Israel said the attacks caused no casualties.

Over the past days, Israel has killed 10 Palestinians, six of them civilians, in different airstrikes and shootings that marked the flare-up of violence.

Gazans expect more Israeli retaliatory strikes after a bomb exploded near a bus stop in Jerusalem Wednesday, killing a woman and wounding more than 20 Israelis. Israel vowed response to the explosion, though no Palestinian group has claimed responsibility for the attack.