PORTLAND, Ore. (KOIN) — Some federal buildings were closed in Portland on Friday due to a “threat of violence.”

KOIN 6 News learned the threat involved a truck carrying explosives. It wasn’t clear which federal building it allegedly intended to target.

Federal buildings including the Portland office of the U.S. Bankruptcy Court, the Gus J. Solomon U.S. Courthouse and the Mark O. Hatfield Courthouse were emptied as a precaution but there were no visible signs of increased security outside of the facilities. Workers at the Wyatt Federal building were told to go home early on Thursday and the building was closed Friday. Workers at the Immigrations and Customs Enforcement building were still fortifying windows, doors and other access points on Friday afternoon.

The FBI in Portland has not ruled out the credibility of this threat.

“If we develop information indicating a credible threat, we will notify the public,” the statement read. “As always, we encourage people to remain vigilant and to promptly report suspicious activities which could represent a threat to public safety.”

“At this point I can tell you that investigation is ongoing,” Beth Ann Steele with the FBI Portland told KOIN 6 News. “Certainly if we determine the information was credible that there was an imminent attack or someone planning an attack we would get that out to the public right away.”

The FBI won’t say how it learned of the threats.

KOIN 6 News also learned downtown Portland city workers were told to go home by noon “out of an abundance of caution” and to stay away through the weekend due to planned demonstrations.

Two child care centers near the federal buildings are also closed for the day, reportedly due to the threat.

If anyone has any information on the situation, please contact the FBI at 1.800.225.5324, or call the local FBI at 503.224.4181. Submit information online here