LONDON (AP) — Britain on Monday barred Belarus’s national airline and instructed U.K. aircraft to avoid Belarussian airspace after a Ryanair passenger jet was forced to land in Minsk.

The government said it was suspending the permit allowing airline Belavia to operate in the U.K.. Transport Secretary Grant Shapps said he had instructed Britain's Civil Aviation Authority “to request airlines avoid Belarusian airspace in order to keep passengers safe.”

A Ryanair flight from Athens to Vilnius, Lithuania, unexpectedly landed in Belarus on Sunday. Ryanair said Belarusian flight controllers told the pilots that there was a bomb threat against the jetliner and ordered them to land in Minsk.

U.K. Foreign Secretary Dominic Raab said the “reckless and dangerous” act by Belarusian authorities was “a shocking assault on civil aviation and an assault on international law.”

He said Britain had “seen no evidence” to support the claim of a bomb threat.

Raab called for the release of Belarusian opposition journalist Roman Protasevich, who was detained when the flight landed, saying he had been detained on “spurious charges.”

He said Britain had summoned Belarus’ ambassador and was conferring with allies about further steps including sanctions.