SAN FRANCISCO (CBS SF) — FBI agents, San Francisco police and fire crews, and a hazardous materials team converged on an apartment building between Jackson and Polk streets Saturday morning, according to San Francisco police.

Police blocked off a section of Jackson Street between Polk Street and Van Ness Avenue.

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Crews wearing hazmat suits were seen going in and out of the building and people were gathered on the roof of the building, according to a witness.

FBI Intelligence Analyst Alice Heller told KPIX 5 the raid was part of a criminal investigation. “There is no threat to public safety. In the interest of agent safety, protective equipment is being used.”

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“Due to the ongoing investigation, I cannot comment further,” said Heller.

Police confirmed that FBI agents were on hand to serve a search warrant, but offered no additional information.

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