'RNC on lockdown': Hazmat team reportedly rushes to GOP's D.C. headquarters

The Republican National Committee headquarters in Washington D.C. was on lockdown Wednesday morning as hazmat teams rushed to the building, according to multiple reports.

The cause of the lockdown at 310 First Street SE Wednesday morning was not immediately revealed by NBC reporter Dasha Burns and the Daily Mail, among the first to report the situation.

"RNC HQ in DC is under lockdown until further notice," Burns told her followers. "Hazmat team is on site sources tell me."

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U.S. Capitol Police alerted Congress that a 'suspicious substance' was under investigation, according to the Daily Mail.

According to the news outlet, a police states: 'Staff and other personnel are directed to AVOID THIS AREA until further notice.'

UPDATE: Officials gave the all clear after investigating a hazardous substance, Fox News correspondent Chad Pergram said just before 9:30 a.m.