Israel is expanding its ground offensive in the Gaza Strip with intensified airstrikes, the Israeli army said Sunday.

The Israeli military said in a statement that it carried out more than 450 airstrikes, targeting sites belonging to Hamas, "including operational command centers, observation posts, and anti-tank missile launch posts," Xinhua news agency reported.

An Israeli officer was severely injured by a mortar shell in the northern Gaza Strip, and a soldier was moderately injured while engaging with militants, the army said.

The two were evacuated to a hospital in Israel to receive medical treatment.

Palestinian media reports said some of the airstrikes targeted the Shifa Hospital, Gaza's largest medical centre where tens of thousands were hospitalised or seeking shelter from the Israeli bombardments.

At least 7,703 people have been killed in Gaza by the Israeli attacks, according to the Gaza-run Health Ministry.

Israel is now preparing for a massive ground operation in the Gaza Strip, as stated by Israeli leaders and senior military officials.