Civilian flights are prohibited in Ukrainian airspace due to a perceived threat.

• Ukranian airspace was restricted for civilian flights, a notice to airmen said.
• After the warning was issued, at least one flight had to turn back.
• Russia launched an attack on Ukraine in the early morning hours local time.

On Thursday, commercial flights were halted in Ukraine due to a "high risk" associated with Russia's ongoing invasion.

Flights scheduled for Thursday on airlines such as Qatar Airways, Wizz Air, and Turkish Airlines in Kyiv have been cancelled.

Russia launched an attack on its neighbor early Thursday morning local time.

Flights to Kyiv scheduled for Thursday were canceled by airlines such as Qatar Airways, Wizz Air, Turkish Airlines, and others.

Just before Russian President Vladimir Putin declared a military operation in Ukraine, a flight restriction notice was issued. Following Putin's announcement, explosions were reported in Ukrainian cities, including Kyiv, the capital.

The European Union Air Safety Agency issued an advisory on Thursday, urging airlines to avoid Ukrainian airspace, including 100 nautical miles of the borders with Belarus and Russia.

Lufthansa and KLM, among other foreign airlines, previously halted flights to Ukraine due to concerns about a possible Russian invasion.

The Warsaw-bound flight of LOT Polish Airlines Flight 755 returned to its departure city around the time the order was issued.

Since the shooting down of Malaysia Airlines Flight 17 in eastern Ukraine, U.S. aviation authorities have prohibited U.S. aircraft from flying over the region. Earlier, Russia had restricted flights along its eastern border with Ukraine.

Due to insurance companies' refusal to cover flights, some Ukrainian airlines were forced to cancel or relocate jets out of the country last week on aircraft lessors' orders.

Some carriers changed their routes.

Our collective evaluation of the situation has led us to proactively transition to an alternate flight routing, which adds additional time to the flight but is a viable alternative to ensure safe and efficient operations. We will continue to monitor the situation and provide updates as necessary.

Follow live updates of the Russian attack here.