Israeli air strikes on the southern and central Gaza Strip killed 14 people on Thursday including seven women and children, medics said, on the third day of a widening military operation.

The first strike hit a coffee shop in the city of Khan Yunis, emergency services spokesman Ashraf al-Qudra told AFP, adding that six men were killed and at least 15 other people wounded.

The second, in Nusseirat refugee camp in central Gaza, on the home of Raed Shalat, killed him and wounded several others, Qudra said.

Further strikes on two houses in Khan Yunis killed seven people - three women and four children, he said.

Dozens of strikes were heard slamming into the besieged Palestinian territory in the early hours of Thursday, as Israel's Operation Protective Edge, the largest military campaign against Gaza since 2012, entered day three.

On Wednesday, 29 Palestinians were killed, and Tuesday's toll stood at 21, bringing the total number of dead to 64.

The dead include at least 10 women and 18 children, according to an AFP count based on medical reports. (AFP)