WATCH LIVE: Obama honors fallen law-enforcement officers

On Saturday, Obama held an annual Police Week ceremony at the White House where he paid tribute to Boston's first responders for their work in finding and capturing the Boston Marathon bombers.

"Our entire country saw once again the strong stuff that these men and women in uniform are made of — police officers, first responders who were running towards explosions, not knowing if there was something more on the way," the president said.

Obama praised the efforts of "law enforcement from different agencies and different parts of the country working together as one united team to identify suspects and bring them to justice and in a moment that few of us will ever forget, the citizens of Watertown, Mass., lining their streets to cheer on and high-five and hug the officers as they headed home after a job well done."

The National Peace Officers Memorial Service began in 1982 as part of National Police Week in Washington, D.C.