"We have information that confirms that Hamas is using that particular hospital for a command and control mode" and probably to store weapons, national security spokesperson John Kirby told reporters aboard Air Force One.

He said the United States had information that Hamas and the Palestinian Islamic Jihad were using some hospitals in the Gaza Strip, including Al Shifa, to conceal or support their military operations and to hold hostages.

A Hamas official in Beirut said 25 of Gaza's 35 hospitals were out of use because of Israel's assault. The fate of Al Shifa in particular has become a focus of international alarm, including from Israel's closest ally, the United States.

Israel denies the hospital is under siege and says its forces allow exit routes for those inside. Medics and officials inside the hospital deny this and say those trying to leave come under fire. Reuters could not verify the situation.