WASHINGTON, Sept. 16 (Xinhua) -- One firefighter was killed and several others were injured in an explosion at a building in Farmington in the northeast U.S. state of Maine on Monday morning, according to officials and local media reports.

The explosion occurred in the morning when firefighters were responding to a smell of propane at a nonprofit site for people with disabilities in Farmington, BNO News reported.

Maine Governor Janet Mills tweeted that she is monitoring the situation and urged residents to avoid the area.