The health ministry in the Hamas-run Gaza Strip said Israeli forces were raiding a hospital Tuesday in the north of the Palestinian territory.
"Israeli occupation forces are storming Kamal Adwan hospital after besieging and bombing it for days," ministry spokesman Ashraf al-Qudra said in a statement.
The Israeli military did not immediately respond to an AFP request to comment.
Qudra said the troops were rounding up men in the hospital courtyard, including medical staff.
"We fear their arrest and the arrest of the medical teams or their killing," the health ministry spokesman added, calling for international intervention.
The United Nations humanitarian agency OCHA said two mothers were killed when the maternity department of Kamal Adwan hospital was reportedly hit Monday.
"The hospital remains surrounded by Israeli troops and tanks, and fighting with armed groups has been reported in its vicinity for three consecutive days," OCHA said.
It said the hospital was "currently accommodating 65 patients, including 12 children in the intensive care unit and six newborns in incubators".
"About 3,000 internally displaced persons remain trapped in the facility and are awaiting evacuation with extreme shortages of water, food and power reported," it added.
Israeli troops have previously raided other medical facilities in Gaza, including Al-Shifa, the territory's largest hospital.
There is currently only one hospital in northern Gaza able to admit patients, according to the UN.
Just 13 of 36 hospitals across the territory are functioning, providing limited healthcare while sheltering thousands of displaced people.
More than 18,200 Gazans have been killed and nearly 50,000 wounded since the war between Israel and Hamas erupted more than two months ago, according to the health ministry.
Around 1,200 people were killed in an unprecedented attack by Hamas militants on southern Israel on October 7, Israeli officials say, which sparked the blistering military response on Gaza.
The majority of war casualties in Israel and Gaza have been civilians.