UNICEF warns intense fighting is now 'dangerously close to al-Thawra hospital' in strategic Yemeni port city.

The battle for the rebel-held city of Hodeidah in western Yemen has placed dozens of children in a hospital "at imminent risk of death", according to the United Nations' children's agency (UNICEF).

The urgent warning on Tuesday came amid reports of fierce clashes between pro-government forces, which are backed by a Saudi-UAE-led military coalition, and Houthi rebels near the strategic Red Sea port, where hundreds of thousands of civilians could be trapped as war closes in.

"Intense fighting in the Yemeni port city of Hodeidah is now dangerously close to al-Thawra hospital - putting the lives of 59 children, including 25 in the intensive care unit, at imminent risk of death," UNICEF said in a statement.

The agency said that medical staff and patients in the hospital in southern Hodeidah city, just 500 metres from the port, heard heavy bombing and gunfire.

"Access to and from the hospital, the only functioning one in the area, is now imperilled," it said.