GAZA -- Israeli air strikes on the Gaza Strip have killed at least 65 people since truce expired and fighting resumed on Friday morning, Palestine's official news agency WAFA reported.

Local medical sources told Xinhua that dozens of others were injured in varying degrees as a result of Israeli raids that targeted several areas of the Palestinian enclave.

The government media office in Gaza said in a statement that Israeli aircraft bombed a number of inhabited homes and crowded areas in several cities of the Gaza Strip.

Al-Qassam Brigades, the armed wing of the Islamic Resistance Movement (Hamas) which controls Gaza, said on Friday it has resumed its attacks on Israeli cities upon the end of the week-long humanitarian ceasefire.

Al-Qassam Brigades said in a press statement that they "targeted the cities of Ashkelon, Sderot, and Beersheba with rocket barrages" in response to the Israeli strikes on Gaza.

In Gaza, al-Quds Brigades, the armed wing of the Islamic Jihad Movement in Palestine, said its fighters attacked an Israeli army unit gathered south of Gaza City using several mortar shells.

Field clashes between Palestinian militants and Israeli forces took place inside and north of Gaza City, according to Palestinian security sources and eyewitnesses.

Meanwhile, sirens were sounding in Israeli towns near their border with the Gaza Strip on Friday morning for the first time since Israel and Hamas reached a humanitarian truce on Nov 24, according to Israeli media.

The Israeli army confirmed that it intercepted a missile fired towards Israel from the Gaza Strip. In the wake of the attack, the Israeli Home Front Command tightened guidelines for civilians in some areas of the country.

The temporary humanitarian truce reached between Israel and Hamas began on Oct 24 and ended at 7:00 am local time (0500 GMT) Friday.

During the ceasefire days, 240 Palestinians, 86 Israelis, and 24 foreign citizens were released.