Law enforcement and a hazmat team are on the scene at the Council on American-Islamic Relations (CAIR) headquarters in Washington, D.C., which has been partially evacuated on Thursday due to a suspicious piece of mail.

CAIR, whose mission is to "enhance understanding of Islam, encourage dialogue, protect civil liberties, empower American Muslims," said on social media that its Capitol Hill office was evacuated by police after a powdery "foreign substance" was found in an envelope.

CAIR Capitol Hill office evacuated by police after "foreign substance" received in mail. https://t.co/fR2laAkQG0

— CAIR National (@CAIRNational) December 10, 2015

According to ABC7, "An unknown number of people who came into contact with the substance were quarantined inside the building."

The Washington Post reports that Ibrahim Hooper, a spokesman for the organization, said "a poof of white powder wafted out of an envelope when a staff member opened it."

The development comes amid escalating xenophobia and anti-Muslim rhetoric, as well as increased reports of attacks based on race and religion.

"We receive threats on almost a daily basis, so it's nothing new for us," said Hooper. "But a suspicious substance—that's new."

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#CAIR Tweets