Russian staff left the consulate last month after Washington ordered Moscow to vacate some of its diplomatic properties, part of a series of tit-for-tat actions as relations sour between the two countries. US officials have since occupied administrative parts of the compound.
Russia said last week they had broken into residential areas and it threatened retaliation over what it called an illegal act. "The latest shameful event. In San Francisco (Russian) flags have been stolen from the building of @ConsulRussiaSF," the Russian embassy to the United States said on its Russian-language Twitter account.
"We demand the American authorities return our state symbols," it said alongside pictures of a bare flagpole on top of the consulate building.
The Russian embassy and US State Department were not immediately available for comment.
"We consider this as an extremely unfriendly step," the embassy said.
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