GAZA CITY (CNN) -- The Israeli military carried out two airstrikes Thursday on vehicles in northern Gaza, killing six Palestinians -- including two civilians, Palestinian security sources said.

One of the strikes hit a wagon carrying an Islamic Jihad militant and his mother, who also was killed, the Palestinian sources said.

A Palestinian civilian driving a nearby car also died in the strike, they said.

Earlier Thursday, Israeli aircraft bombed a car and killed three members of the Popular Resistance Committee's military wing, Palestinian security sources and witnesses said.

Both strikes happened near Beit Lahya, they said.

The Israeli military confirmed two airstrikes in the region, saying the second one targeted a rocket-launching squad after it fired a spate of Qassam rockets toward Israel.

Under pressure to stop ongoing attacks from Gaza, the Israeli military has clamped down on the Palestinian territory in recent days.

Palestinian militants fired at least 33 rockets Thursday from Gaza into Israel, the Israel Defense Forces said.

Two rockets landed in the central Israeli town of Sderot, one hitting a house and causing major damage, the IDF said. The IDF identified the devices as Palestinian Qassam rockets, which are crudely made and unguided missiles packed with explosives.

Israeli troops then launched two strikes on militants who fired the rockets, the IDF said.

On Tuesday, an Israeli raid in Gaza City killed 19 Palestinians, including the son of senior Hamas official Mahmoud al-Zahar.

Hamas said it responded by firing 15 rockets into Israel, most in or around Sderot. Five people were wounded, according to Israeli medical services.

As Tuesday's IDF operation was under way, snipers near the Gaza border fired into Israel, fatally striking a kibbutz farmer, according to emergency officials and the IDF.

On Wednesday, an errant Israeli airstrike in Gaza killed three members of a family in a car. The Israeli military confirmed the missile, intended for a car carrying militants, struck the wrong vehicle. A spokeswoman said the military regrets the loss of innocent life but stressed militants put civilians at risk by operating in populated areas of Gaza.