World Bulletin / News Desk

Offices at the largest U.S. Muslim civil liberties organization were evacuated Thursday after a suspicious material was received in the mail.

The Capitol Hill offices at the Council on American-Islamic Relations in Washington received an envelope containing a white powdery material.

The incident comes after series of high-profile terror attacks, including a deadly mass shooting in California that killed 14 victims last week. Authorities are investigating the attack as terrorism. Republican presidential candidate Donald Trump’s earlier this week demanded a ban on all Muslims entering the U.S..

CAIR was among the first to condemn Trump’s proposal but the organization that is accustomed to defending attacks now finds itself a victim.   

"We receive hate messages daily because of our advocacy on behalf of the American ‪‎Muslim community. It's frightening to experience the hate manifest itself to such a real level,” said Maha Sayed, one of the organization’s staff attorneys.

“This will not deter us from continuing to protect the civil rights and liberties of all Americans,” she added.

CAIR Executive Director Nihad Awad and Communication Director Ibrahim Hooper said there was a hate message in the envelope.

“Preliminary field tests indicate the substance is not dangerous, letter is now in the hands of the FBI for more extensive tests,” CAIR said on Twitter.

"The number of recent threats have gone up significantly since Trump’s comments, San Bernardino shooting and Paris attacks,” Awad told reporters.

CAIR posted a video of the evacuation on its social media accounts.