LONDON — The Russian Embassy in London on Saturday sought a meeting with Britain’s foreign secretary, Boris Johnson, over the poisoning of a former Russian spy, saying its dealings with Britain over the issue had been “utterly unsatisfactory.”

Britain replied that “it’s Russia’s response that has been unsatisfactory,” as the two countries continued a bitter public feud over the nerve-agent attack.

The Russian Embassy said in a statement that it was “high time” for a meeting between Mr. Johnson and its ambassador, Alexander Yakovenko, to discuss the investigation into the poisoning of the spy, Sergei Skripal, and his daughter, Yulia, and “the whole range of bilateral issues.”

The British Foreign Office said it had received the request and would respond “in due course.” But in a statement it accused Russia of employing a “diversionary tactic” and refusing to “engage constructively” and answer questions about the attack.