UPDATE: Two men probed in Boston Marathon bombings cleared by investigators

Investigators probing the deadly Boston Marathon bombings are circulating photos of two men spotted chatting near the packed finish line, The Post has learned.

In the photos being distributed by law-enforcement officials among themselves, one of the men is carrying a blue duffel bag. The other is wearing a black backpack in the first photo, taken at 10:53 a.m., but it is not visible in the second, taken at 12:30 p.m.

“The attached photos are being circulated in an attempt to identify the individuals highlighted therein,” said an e-mail obtained by The Post. “Feel free to pass this around to any of your fellow agents elsewhere.”

Meanwhile, officials have identified two potential suspects who were captured on surveillance videos taken shortly before the deadly blasts, law-enforcement sources told The Post yesterday.

Authorities know the names of the two men, but do not have enough evidence to make an arrest for Monday’s attack, which killed three and wounded 176, the sources said.

It was not immediately clear if the men in the law-enforcement photos are the same men in the surveillance videos.

The developments came as:

* Leaked photos show that the 6-liter pressure cookers stuffed with metal projectiles was powered by a $3 battery typically used in kids’ toys.

The pictures also included the circuit board, pieces of the shrapnel and twisted chunks of metal from the Fagor pressure cooker.

* The lid of one pressure-cooker bomb was blown off with such force that it landed on the roof of the Charlesmark Hotel 35 yards away, investigators believe.

A guest mistook it for a hubcap and gave it to authorities.

* The federal courthouse in Boston was evacuated when a caller phoned in a bomb threat following erroneous reports of an arrest. A threat was also called in to Brigham and Women’s Hospital, where several victims were being treated.

* President Obama and the first lady are scheduled to visit Boston today to attend an interfaith prayer vigil with Gov. Deval Patrick.

They also plan to visit some of the wounded victims. There are 14 people in critical condition, but all are expected to survive.

Investigators continued to sift through clues from the powerful blasts as the suspects remained at large. They took items from the home of Carlos Arredondo, the cowboy-hat-wearing peace activist who bravely helped some of the wounded spectators, including a man who lost both legs.

“They took my clothes, my shoes, my pants, my T-shirt — whatever they needed I provided to them,” he told Boston’s WBZ-TV.

Officials have also asked people to turn in any cellphone video or photos taken at the bomb sites.

Fagor America, the company that made the pressure cooker, said it was contacted by investigators and is cooperating.

The battery maker, Tenergy, said on its Web site: “Everyone at Tenergy is deeply saddened by the recent events at the Boston Marathon. Our hearts and thoughts are with the victims, their families and the Boston community.”

Nobody has claimed responsibility for the attack, which is believed to be a domestic plot rather than international terrorism.

Mayor Bloomberg, meanwhile, said New York will remain on high alert. There were at least 94 reports of suspicious packages yesterday, although none proved to be a legitimate threat.

The Times Square subway station was evacuated when someone reported a suspicious package at West 42nd Street and Seventh Avenue. Also, cops cleared a Brooklyn Heights bank over a report of a suspicious package, which turned out to be a cup of coffee.

On Tuesday, there were 77 reports that were resolved.

Meanwhile, Port Authority Police officers were in Boston yesterday offering support and refreshments to weary Boston cops.

“We received a lot of support from other agencies after 9/11, when we lost 37 of our police officers,” said Officer Brett Porigow.

“There’s a kinship and a brotherhood . . . that we all share.”

Additional reporting by Lorena Mongelli and Kate Kowsh in Boston