Israel's military has confirmed that its jets carried out an attack on the Jabalia refugee camp in Gaza.
The camp is in northern Gaza - an area where Israel has told people to leave for their safety.
The Israeli Defence Force says the strike killed a senior Hamas commander and caused the collapse of Hamas' underground infrastructure.
Meanwhile, the Hamas-run health ministry and a hospital director say at least 50 people were killed and pictures from the scene show craters and levelled buildings.
Israel says it hit 300 targets in Gaza overnight as its air strikes and ground offensive continue.
The IDF says its ground forces were attacked by "terrorists" with anti-tank missiles and machine gun fire.
The Hamas-run health ministry in Gaza says more than 8,500 people have been killed since Israel's retaliatory bombing began.
Source: BBC News
