ATLANTA — Initial tests show suspicious letters sent to a Georgia congressional candidate, news outlets and others did not contain dangerous materials. But the FBI says authorities will conduct additional tests.

In a statement Friday, the FBI said the envelopes contained a white powder. The statement says all the letters contained “threat based content” but have tested negative for hazardous materials.

One delivery was sent to the suburban Atlanta home of Republican Karen Handel, a candidate in Georgia’s 6th Congressional District runoff election set for Tuesday. Several others were sent to or intended for her neighbors. Two Atlanta television stations also were apparent targets.

Handel says she’s cooperating with authorities.

She faces Democrat Jon Ossoff in a nationally watched matchup that Democrats want to turn into a referendum on President Donald Trump.