Washington has returned Russian flags taken from the San Francisco consulate building the U.S. had seized as part of a spat over claims of election interference and diplomatic staff cuts.

Moscow warned of retaliation after what it described as the illegal removal of its archives and “extremely unfriendly” flag removals from the consulate building this month.

“Yes, the flags were returned, the archive was returned from the Russian consulate general in San Francisco,” the state-run TASS news agency cited Deputy Foreign Minister Sergei Ryabkov telling journalists on Wednesday.

Ryabkov repeated Moscow’s warnings that it reserves the right to take similar steps against U.S. diplomatic missions in Russia. “We are warning the American side that these things are not forgotten.”

Ryabkov criticized the treatment of Russia’s state symbols as “nothing less than provocative.”

“The fact that they handed them to us is a matter of course, make no mistake about it. But everything that preceded this still causes our strong rejection and zero tolerance,” he stressed.

Russia was ordered to vacate its San Francisco consulate and two other consular annexes after Moscow instructed the U.S. to reduce its diplomatic mission by hundreds of people. The demand followed a vote to tighten sanctions on Russia.

Moscow called the move a response to the previous U.S. administration’s seizure of two Russian diplomatic compounds and the expulsion of dozens of Russian diplomats in December 2016 over allegations of election interference.