Israel has mounted several raids at and near hospitals in Gaza since the war began last October, claiming that fighters are operating in medical complexes -- a pretext for Israel to carry out war crimes against displaced and wounded Palestinians sheltering inside.

Military vehicles approached Nasser and Al-Amal hospitals in southern Gaza's Khan Younis as heavy bombardment and gunfire echoed in the area, the Red Crescent said.

The medical organisation said a volunteer worker at the hospital was killed by Israeli gunfire early Sunday.

The Red Crescent said messages broadcast from drones demanded that everyone in Al-Amal leave naked, while forces blocked the gates of the hospital with dirt barriers.

"All of our crews are currently under extreme danger and cannot move at all," the group added.

Israeli forces launched an extensive raid early Monday that is still going on, in and around Gaza's largest hospital, Al-Shifa.

The Israeli army says it has killed some 170 Palestinians and detained hundreds more during the days-long raid.

The military previously raided the facility last November, sparking international criticism.

Israel has also previously carried out operations around Al-Amal, with the Red Crescent in February saying the military had engaged in a multi-day siege of the facility.

*This story was edited by Ahram Online