The FBI has released images and video of two suspects in the Boston Marathon bombing at fbi.gov.

The images appear to show two men, one in a dark baseball cap and one in a white baseball cap, each carrying a backpack. The FBI apparently does not know their identities and is seeking tips. The FBI did not provide any physical descriptions or other information beyond the images.

At a press conference televised this afternoon, FBI officials did not say exactly why the men are considered suspects.

Anyone who believes they can identify the men can contact the FBI at 1-800-225-5324. A website specifically for submitting tips in this case, including photos and videos, at bostonmarathontips.fbi.gov. The FBI considers the suspects armed and dangerous