More airlines are likely to avoid Ukraine's airspace amid insurance issues and a decision by leading European carriers to stop overflights after a US warning that Russia could invade at any time, a flight operations advisory firm says.
Dutch airline KLM said it would halt flights to Ukraine and through the country's airspace, while Germany's Lufthansa said it was considering a suspension.
British Airways (BA) flights between London and Asia on Monday appeared to be avoiding the airspace, according to Reuters monitoring of flight tracking service FlightRadar24.
"My guess would be that Ukraine will become unavailable pretty soon if what we've seen over the weekend crystallises into a couple of more carriers actually pulling the pin," said Mark Zee, founder of flight operations advisory firm OPSGROUP.
Malaysia Airlines flight MH17 was shot down over eastern Ukraine in 2014, killing all 298 people on board, two-thirds of them Dutch citizens and 38 of them Australian residents. Some airlines were already avoiding the airspace after earlier shoot-downs of military aircraft.
News agency Interfax Ukraine said Ukrainian insurance companies had received a notification from reinsurers that airlines were not covered for war risks.
US and Ukrainian leaders speak
US President Joe Biden spoke has spoken at length with Ukrainian counterpart Volodymyr Zelensky about Russia's military buildup along Ukraine's borders, with the pair committing to pursue "diplomacy and deterrence," the White House said.
"The two leaders agreed on the importance of continuing to pursue diplomacy and deterrence in response to Russia's military build-up on Ukraine's borders," according to a readout of the roughly 50-minute call held on Sunday.
"President Biden reaffirmed the commitment of the United States to Ukraine's sovereignty and territorial integrity," the White House added, referring to the American president's position he has established on multiple occasions when addressing Moscow's brinkmanship.
With Western fears growing that Russia is about to invade the ex-Soviet state, the readout added that Mr Biden "made clear that the United States would respond swiftly and decisively, together with its allies and partners, to any further Russian aggression against Ukraine."
A Ukrainian tank moves during military drills close to Kharkiv, Ukraine. Source: AP
The US and its allies have warned that Russia has massed well over 100,000 troops on its borders with Ukraine.
Earlier on Sunday, top American officials offered grim assessments of the situation, with US national security advisor Jake Sullivan saying a Russian invasion of Ukraine could begin "any day now," and would likely start with "a significant barrage of missiles and bomb attacks" leading to civilian deaths.
The US picked up intelligence that Russia was looking at Wednesday as a target date, according to a United States official familiar with the findings.
"We're not going to give Russia the opportunity to conduct a surprise here, to spring something on Ukraine or the world," Jake Sullivan, the US national security adviser, told CNN on Sunday, about the United States' warnings.
"We are going to make sure that we are laying out for the world what we see as transparently and plainly as we possibly can," he said.
The US has largely not made public the evidence it says is underlying its most specific warnings on possible Russian planning or timing.
Armored vehicles move at the Gozhsky training ground during the Union Courage-2022 Russia-Belarus military drills in Belarus, a neighbouring country of Ukraine. Source: AAP
The Russians have deployed missile, air, naval and special operations forces, as well as supplies to sustain an invasion.
This week, Russia moved six amphibious assault ships into the Black Sea, augmenting its capability to land on the coast.
Pentagon spokesman John Kirby said on Sunday that Russia had well over 100,000 troops along Ukraine's borders, "and actually, over the last few days, even more".
Mr Kirby cited "a mosaic of intelligence" the US had gathered, but gave no details.
But Mr Zelensky has played down intensified warnings of a possible Russian invasion within days, saying he has yet to see convincing evidence.
His comments this weekend indicated frustration at the warnings from Washington, as he tried to minimise damage to Ukraine's economy during the crisis.
"We understand all the risks, we understand that there are risks," he said in a live broadcast.
"If you, or anyone else, has additional information regarding a 100 per cent Russian invasion starting on the 16th, please forward that information to us."
Mr Biden on Saturday held an hour-long call with Russian President Vladimir Putin.
But with that conversation failing to move the needle or significantly tamp down sky-high tensions, Mr Kirby said that was "certainly not a sign that things are moving in the right direction."
With additional reporting by AAP.
