Turkish Transport Minister Binali Yildirim said on Wednesday Russia’s refusal to issue visas to crew members working for budget carrier Pegasus was an “arbitrary” measure and violated international aviation rules.

Istanbul-based Pegasus said on Tuesday it suspended flights to and from Russia until Jan. 13 after authorities in Moscow failed to give its crew visas.

Turkey would use diplomatic channels to appeal to Russia to abide by “international norms,” Yildirim said at a news conference.

But the Russian Foreign Ministry said Pegasus had only applied for visas at the Russian consulate in Istanbul on Wednesday afternoon, and that Onur Air, which has suspended its flights to Russia until Jan. 14, had not applied at all.

In a statement, it said Russia had provided multiple one-year visas to 380 crew members and technicians at Turkish Airlines, which had “started tackling this problem on time … and is now making flights according to schedule”.