5:01 p.m. update: And now Maine Avenue has reopened, according to police.

4:44 p.m. update: I-395 has fully reopened, but Maine Avenue is now blocked, police report. Again, watch for lingering delays.

4:37 p.m. update: I-395 has partially reopened in D.C., according to police. However, heavy delays remain approaching this spot, so try to avoid the area. Original post:

A tour bus caught fire Monday afternoon and forced authorities to shut down a portion of Interstate 395 at the start of the evening commute.

Firefighters responded to the fire on southbound I-395, near the 12th Street exit, about 3:45 p.m., officials said. No injuries were reported immediately.

The incident closed all southbound lanes of traffic, D.C. police officials said.