Hamas on Thursday released video showing their militant fighters ambushing and firing weapons at Israeli targets operating inside the embattled Gaza Strip as Israel announced a more targeted approach in hunting down Hamas fighters and their leaders.

Reuters was not able to independently verify the footage.

Israeli shelling of Gaza on Thursday killed more than 20 Palestinians, including 16 in Khan Younis city in a southern coastal area packed with people who had fled from other parts of the enclave, Gaza health officials said.

Israel's war against Hamas is nearing the three-month mark amid international concern that the conflict is spreading beyond Gaza, drawing in the Israeli-occupied West Bank, Hezbollah forces on the Lebanon-Israel border, and Red Sea shipping lanes.