Authorities in the Ukrainian capital on Monday asked residents to resume wearing face masks due to a surge in Covid cases and a health system battered by the Russian invasion.

In the past week, 2,515 coronavirus cases were registered in Kyiv, 242 people were hospitalised and 22 people died, the city hall said.

Residents should wear a mask in "public transport, in places that serves clients, and in educational facilities", it said.

Between September 19 and September 25, there were 44,137 new registered cases in Ukraine, 6,667 people were hospitalised, and 161 people died, the health ministry said.

Last Monday, Deputy Health Minister Igor Kuzin spoke of an "increase" in Covid cases and said the healthcare system was "suffering losses every day" because of the war.

"Since the beginning of the invasion, 18 facilities welcoming Covid patients were destroyed, another 15 were partially destroyed, and more than 100 are under forced occupation," Kuzin said.

Kuzin also said Covid curbs could be hard to implement as the country was "focusing on another enemy."

Covid restrictions were suspended when martial law was established in Ukraine on February 24, the day Russia invaded the country.

The peak in cases is expected between the end of September and the start of October, according to Kuzin.

The World Health Organization (WHO) said at the end of August that Ukraine's health system was "badly affected but still resilient".

As winter approaches, the WHO said "the next six months could test Ukraine's health system like never before."