Airlines are bracing for potentially lengthy blockages of key east-west flight corridors after the European Union and Moscow issued tit-for-tat airspace bans and Washington pondered similar action in response to Russia's invasion of Ukraine.

U.S. officials said Washington had yet to make a final decision on whether to follow Europe and Canada in banning Russian airlines from using their airspace.

But a European official, who asked not to be identified, said the EU had full confidence Washington would follow suit.

A move by the White House to ban Russia's carriers is expected to provoke a response from Moscow, which could affect carriers like United Airlines. The Chicago-based carrier uses Russian airspace for flights to India.

Russia on Monday banned airlines from 36 countries including all 27 members of the European Union after EU ministers agreed to refuse entry to Russian airplanes including the private jets of the country's oligarchs.

The sanctions sparked flight cancellations and costly detours, denting the industry's pandemic recovery and dealing a blow to the mainly Ireland-based leasing industry which was ordered to stop dealing with Russian airlines.

The rerouting meant Kazakhstan's airspace saw a tripling of flights to more than 450 on Monday.

Without access to Russia's airspace, many carriers will have to divert flights south while also avoiding areas of tension in the Middle East.

FINNAIR SHARES PLUNGE

Finnish national carrier Finnair canceled flights to Japan, Korea, China and Russia and scrapped 2022 guidance, as sanctions block access to Asia - a cornerstone of its strategy in recent years due to its Helsinki hub's location.

Shares in Finnair plunged 21%, leading a retreat in airline stocks which fell more than 4% in Europe and the United States.

Germany's Lufthansa group said 30 flights to Russia would be canceled this week while Latvia's AirBaltic said it was extending a suspension of flights to Russia until the end of May.

Lufthansa said its flights from Europe to Tokyo and Seoul would have to fly detours for which the company had secured necessary flight rights.

Swiss, also owned by Lufthansa Group, canceled Monday's flight from Zurich to Moscow, citing what it said was an unclear regulatory situation, and said it was not flying through Russian airspace.

Russia's Aeroflot said on Sunday it would cancel all flights to European destinations.

On Monday, however, an Aeroflot jet headed to Verona in Italy was forced to enter a holding pattern outside EU airspace and was diverted to Turkey after apparently being refused access, according to flightradar24.

That came hours after one of its flights crossed Canadian airspace despite Toronto's ban on Russian planes, prompting a regulator to launch a review into the conduct of Aeroflot and Canada's air-traffic control service provider.

FURTHER DISRUPTION

Among other disruptions, Gulf carrier Flydubai canceled flights to Krasnodar and Rostov-on-Don in Russia until March 8, but said it would continue flights from Dubai to Moscow and seven other Russian destinations.

In Asia, Singapore Airlines said it was suspending all services between Singapore and Moscow until further notice.

Korean Air, Japan Airlines and Japan's ANA Holdings said on Monday they were continuing to use Russian airspace but had no plans to add flights to Russia or Europe to replace flights canceled by European carriers.

Demand to Japan and South Korea has been low due to COVID-related travel restrictions.

Airspace shutdowns and flight cancellations also started to affect cargo traffic, further exacerbating global supply chain woes caused as the pandemic slows cargo handling worldwide.

Many cargo carriers use Russian airspace, which is a major intersection for global trade, about half of which by value is carried by air.

UPS, FEDEX JOIN BANDWAGON

"Due to the ongoing dramatic developments in the Russia-Ukraine conflict, Lufthansa will no longer use Russian airspace," Lufthansa Cargo said.

U.S.-based United Parcel Service Inc and FedEx Corp., two of the world's largest logistics companies, said they were halting deliveries to Russia.