MOSCOW — Edward J. Snowden, the former National Security Agency analyst who fled to Russia last year after releasing reams of secret American government documents, has applied to extend his temporary asylum, his lawyer was quoted as telling Russian news agencies on Wednesday.

Anatoly G. Kucherena, the lawyer, said that he had asked the Moscow branch of the Federal Migration Service to permit Mr. Snowden to remain in Russia after his initial one-year asylum expires on July 31.

“We have submitted documents for extending his stay in Russia,” Mr. Kucherena was quoted as saying by Interfax.

The decision by Russia to grant Mr. Snowden asylum last year was a major source of tension with Washington, prompting President Obama to cancel a meeting with President Vladimir V. Putin. It was one of a series of events, including the annexation of Crimea in March, that brought ties between Russia and the United States to their lowest point since the Soviet Union disintegrated in 1991.