WASHINGTON (NEXSTAR) -- The search for a suspect is underway after someone set fire to two ballot drop boxes in Oregon and Washington Monday.  Portland police say a third fire earlier this month is believed to be connected. They say the suspect is an experienced metalworker and may be planning more attacks. "It is unacceptable. It is unacceptable," White House Press Secretary Karine Jean-Pierre said Wednesday.  The White House condemned the incidents, and said the FBI is investigating.  "Every eligible American has the right to make their voices heard," Jean-Pierre said.  Local officials say the fire in Vancouver, Washington damaged 488 ballots. The county is identifying impacted voters to receive replacement ballots.  In Portland, Oregon, which Congresswoman Suzanne Bonamici (D) represents, three ballots were damaged.  "That's three too many, but there is a way for the elections office to contact the voters and to have them come in and do a replacement ballot," Bonamici said.  Bonamici says security has since stepped up around drop boxes, with cameras or law enforcement. She's still encouraging voters to cast their ballots and says the election is safe.  "So please don't be afraid. This is an important election," Bonamici said.  The devices used to set the fires were marked with the message "Free Gaza" according to a law enforcement official who spoke to the Associated Press.  Other cities are on high alert.  "We will pay special attention to ballot box drop off locations and our polling places," Washington, D.C., Police Chief Pamela Smith said.  Chief Smith says there are no known threats right now, but the city is prepared with more police presence.  "We will not stand for any instance of voter intimidation or disruption in this electoral process," Smith said.