Law enforcement officials released the images of two possible suspects in Monday’s Boston Marathon bombing in an attempt to gain public support in identifying them.

Officials described “suspect one” as a male wearing a dark baseball cap and “suspect two” as a male wearing a white baseball cap based on footage gathered from surveillance cameras near the crime scene.

“Today we are enlisting the public’s help to identify two suspects,” said Richard DesLauriers, special agent in charge of the FBI in Boston. “After a very detailed analysis of photo, video and other evidence, we are releasing photos of these suspects.”

Images and video of the two suspects were made available to the public online. Officials encouraged the public to visit bostonmarathontips.fbi.gov with any information relating to the suspects or investigation.

“For more than 100 years, the FBI has relied upon the public to be its eyes and ears,” DesLauriers said. “… We know the public will play a critical role in identifying these individuals.”

DesLauriers said the two suspects appear to be associated with one another. Officials consider them to be the only two persons of interest at this time.

“We considered them to be armed and extremely dangerous,” DesLauriers said.

The two suspects were seen walking together on Boylston Street in the area of Gloucester Street on a camera, DesLauriers said.

Suspect two was observed placing a backpack at the site of the second explosion in front of the Forum restaurant at 755 Boylston St. by a surveillance camera, he said. He encouraged anyone who was at Forum on Monday to contact investigators.

“The only one who was observed planting the device was suspect two with the white cap … it was shortly before the explosions,” DesLauriers said.

After the explosions, suspect two proceeded west on Boylston Street.

DesLauriers said it is important that citizens contact law enforcement officials rather than take matters into their own hands.

Boston Police Department Commissioner Ed Davis, Massachusetts State Police Colonel Timothy Alben and U.S. Attorney Carmen Ortiz joined DesLauriers at the conference in the Sheraton Hotel along with other federal agents.

The news comes three days after the FBI launched an investigation into the Monday attacks. Three people were killed, one of whom was a BU graduate student, and 176 were injured in two explosions near the finish line of the Boston Marathon.

Forensic experts recovered what they believe to be fragments from a bomb made with a pressure cooker. The pressure cookers were packed with shrapnel such as BBs and nails, which added to many of the injuries. They believe the devices were transported in black nylon bags or backpacks.

On Wednesday, there was confusion as conflicting reports emerged that a bombing suspect had been detained. However, FBI and BPD officials both denied this news at the time.

“The horror of that day [Monday] will remain with us forever,” DesLauriers said. “… The FBI is committed to ensuring that the victims receive the rights they are entitled to and the assistance they need.”

UPDATE: The FBI released new photos of the two suspects Friday morning at 2 a.m.