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.

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