U.S. Rep. Alexandria Ocasio-Cortez, D-N.Y., said Tuesday that one of her district offices was mailed a suspicious envelope. Pool Photo by Adam Gray/UPI

Oct. 21 (UPI) -- At least nine U.S. lawmakers announced Tuesday that suspicious envelopes had been mailed to their offices, the latest in a wave of similar mailings targeting federal legislators from both parties in the past week.

More than three dozen senators and House members have reported receiving suspicious envelopes, some containing white powder or unknown substances, or having them intercepted by postal investigators. The mailings were first reported Oct. 13, when suspicious letters were received by the offices of elected officials in Louisiana and Oklahoma.

On Tuesday, lawmakers who announced...