Pictured: premature babies left behind as Russians hold '500 patients and staff hostage'

Premature babies have been left behind in Mariupol as Russian forces fire from a hospital with 500 patients and staff held hostage, according to reports.

Troops stormed houses and rounded up 400 residents on Tuesday evening, forcing them into the southern city’s hospital number two alongside 100 patients and doctors.

Regional governor Pavlo Kyrylenko said it is “impossible to leave the hospital” and that the Russians are “shooting hard”.

Nearby in hospital number three, premature babies have reportedly been left without their parents.

Residents in Mariupol are desperately fleeing, with around 20,000 escaping via a humanitarian corridor. The exodus saw at least 4,000 cars abandoned at the 160-mile long route.

But despite many fleeing, staff at Mariupol hospitals are trapped behind with seriously ill patients amid heavy bombardment.

Mr Kyrylenko said that hospital number two’s main building was seriously damaged by shelling and that doctors are treating patients in its basements. The hospital is known as the city’s intensive care unit.

He asked the West to respond to the “gross violations of the norms and customs of war, these egregious crimes against humanity”.

Russian troops are attempting to barricade the city from Ukrainian forces from the west and east. The Ukrainian army's General Staff said: “There are significant losses”.

Almost 400,000 people are still trapped without running water.

The government is struggling to provide humanitarian aid to the city’s residents, Iryna Vereshchuk, the country’s deputy prime minister, said.

A convoy of supplies bound for Mariupol was hit at nearby Berdyansk. Ms Vereshchuk accused Russia of making misleading promises about agreeing to help civilians.

According to the Red Cross, hundreds of thousands of those stuck are being “suffocated” with “no aid”.

Ewan Watson, a spokesman for the International Committee of the Red Cross, said that the city was in “an extreme situation of life and death where people are facing impossible choices to feed their families”.