Kazakhstan has seen an increased number of arrivals from neighbouring Russia, Kazakh authorities said on Friday, after Moscow announced a conscription drive this week the war in Ukraine.
President Vladimir Putin on Wednesday ordered Russia's first mobilisation since World War Two and backed a plan to annex swathes of Ukraine, prompting an exodus of conscription-age men from the country.
Four of 30 road checkpoints on the Russian-Kazakh border - the world's second-longest - were particularly congested, Kazakhstan's border guard service said in a statement, without providing any numbers on arrivals.
A witness who asked not to be named, fearing for his safety, said they had been in a queue at a border checkpoint since Thursday morning and saw unusually heavy traffic from the Russian side and lengthy, thorough checks of Russian cars by Russian border guards.
Many of those seeking to cross the border were men who appeared to be of conscription age, under 35, the witness said.
Kazakh truck drivers crossing the border have published videos online showing long queues of made up mostly of passenger cars.