PORTLAND, Ore. (KOIN) -- Investigations are underway after authorities say incendiary devices were placed near ballot boxes in Portland, Oregon, and Vancouver, Washington, and used to start the fires in the early morning hours of Monday.

It's unclear at this time whether the incidents were connected; however, Vancouver police say the Federal Bureau of Investigation is investigating the incident in Clark County.

According to Portland police, at around 3:30 a.m. on Monday, officers responded to reports of a fire at a ballot box on Southeast Morrison Street, near the Multnomah County Elections Division office. By the time officers arrived, they said the fire had already been put out by security employees who work in the area.

Authorities said they found that an incendiary device had been placed in the ballot box and used to start the fire.

Information about the incident is still limited and authorities are asking anyone with information to contact Portland police or Portland Fire & Rescue.

Just half an hour later, Vancouver police said a Clark County ballot box was also found to be on fire.

When officers arrived at the scene, they said that the ballot box at 3510 SE 164th Avenue was smoking and on fire, and the Metro Explosive Disposal Unit arrived to collect the explosive device.

The incident is under investigation by the FBI, Vancouver authorities said. It's unclear how many Clark County ballots were damaged at this time.

Tim Scott, Multnomah County's elections director, said fire suppressant inside the ballot box on Southeast Morrison helped protect the ballots inside, and that only three ballots were damaged.

Multnomah County's Elections Office will contact those voters via unique identifiers on their ballot envelopes in order to receive replacement ballots.

"We have multiple systems and security measures in place to ensure your ballot is safe," Scott said in a statement. "Your Elections team is working hard to make sure that every vote counts."

A similar situation happened in early October near a ballot box in Vancouver.

In the incident, authorities said the ballot box wasn't compromised and the suspicious device was safely removed by the bomb squad.