Doctors are faced with rising numbers of people wounded as a result of the war - and in Mariupol, there are fears of a humanitarian catastrophe as residents are left without heating, electricity or access to clean water.

Médecins Sans Frontières (MSF) said pharmacies in the besieged city have run out of medicine and people are having to break open heating systems just to wash their hands.

Meanwhile, cities like Odessa are preparing for further attacks and siege as Russian forces advance.

Alex Wade, emergency coordinator for MSF, said it is crucial that more supplies can get to hospitals in the country.

Speaking to Sky News from Lviv, he said: "Hospitals we are in contact with are reporting rising numbers of people injured as a direct result of the conflict - war wounded, shrapnel injuries, etc.

"These people need urgent care and often trauma and/or surgical interventions.

"At the same time, hospitals are reporting that they are running out of supplies to treat these severe injuries as well as patients with chronic illnesses."

MSF - also known as Doctors Without Borders in English - has been working to ensure the right medical supplies reach the right places in Ukraine as hospitals in the country come under intense strain.

Mr Wade added: "Logistically, it is incredibly challenging getting much needed supplies into the country right now and with this war evolving so rapidly, we are in a race against time to get medications and equipment to towns before they risk getting shut off."

On Saturday, MSF says it was able to get 120 cubic metres of medical supplies into Ukraine - a third of which was immediately rushed on to Kyiv by train for use in hospitals in the capital and in towns further east.

Key developments:
• A US defence official says Russian soldiers are edging closer to Kyiv
• Satellite images suggest a large convoy of Russian troops has dispersed and redeployed
• Boris Johnson has told Sky News it has been "deeply upsetting" to reject calls for a no-fly zone over Ukraine
• The UN Security Council will meet today to discuss Russia's claims that the US and Ukraine are developing biological weapons - despite firm denials from both countries
• Ukraine has told the UN's nuclear watchdog that all contact with the Chernobyl power plant has been lost

Mr Wade added: "An important focus for the MSF teams will be to ensure that we able to provide the right medical supplies to the right hospitals at the right time, based on their needs and the challenges they are facing.

"We are also running mass casualty trainings in a number of different areas."

MSF is appealing for donations from the public so that it can continue its work in Ukraine and elsewhere.