MOSCOW — President Vladimir V. Putin on Monday named a career diplomat and arms control expert who is under European Union sanctions as the next Russian ambassador to Washington, replacing an envoy drawn into the swirling questions surrounding contacts between the Trump campaign and the Kremlin.

The appointment of Anatoly I. Antonov, 62, a deputy foreign minister and, somewhat unusually for a diplomat, a former deputy defense minister, had been anticipated. He will start on Sept. 1, said Maria Zakharova, the spokeswoman for the Foreign Ministry.

Ambassador Sergey I. Kislyak, 66, who has been the Russian envoy to the United States since 2008, is due to retire from the diplomatic service. He had told associates earlier this year that the controversy surrounding his meetings with Trump advisers prompted many in Washington to avoid him, and had made the American capital a lonely place.

Mr. Antonov is stepping into a demanding assignment after nearly 30 years in the Russian diplomatic service, where he has been a deputy foreign minister since December 2016. He has been described as a determined negotiator and a hard-liner regarding relations with the United States but also a realist who has echoed the official line that the two countries have too many overlapping interests not to cooperate.