According to CNN, a circular sent out Wednesday to federal and state agencies features the photos "in an attempt to identify the individuals," who were described as being of "high interest" to investigators.
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One of the men is seen carrying a black backpack.
According to the official, authorities had not yet identified the two men by name and the photographs were not being released to the public for fear of impeding the investigation.
Earlier on Wednesday, Massachusetts Gov. Deval Patrick said investigators were closer to cracking the case "every hour." But he urged patience with the probe.
Investigators are on the hunt for a man seen in a department-store surveillance video dropping off a bag at the site of the bombings that killed three people, a Boston politician said Wednesday.
Separately, a law enforcement official confirmed that authorities have found an image of a potential suspect but don't know his name.
City Council President Stephen Murphy, who said he was briefed by Boston police, said investigators saw the image on surveillance footage they got from a department store near the finish line, and matched the findings with witness descriptions of someone leaving the scene.
"I know it's very active and very fluid right now - that they are on the chase," Murphy told The Associated Press. He added: "They may be on the verge of arresting someone, and that's good."
One department store video "has confirmed that a suspect is seen dropping a bag near the point of the second explosion and heading off," Murphy said.
A law enforcement official who spoke to AP on condition of anonymity and was not authorized to discuss the case publicly confirmed only that investigators had an image of a potential suspect whose name was not known to them and who had not been questioned.
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