MOSCOW, October 30. /TASS/. The number of work permits issued to foreigners in Russia that were deemed invalid has increased by 3.5 times, Russian Interior Minister Vladimir Kolokoltsev said during the ministry board meeting on working with migrants.

"The number of patent deemed invalid has increased by 3.5 times," he said.

At the same time, the list of grounds for invalidation of work permits and citizenship has been expanded.