US President Barack Obama says the capture of the other suspect in the Boston Marathon bombing closes what he calls "an important chapter in this tragedy."
Obama spoke from the White House shortly after police took 19-year-old Dzhokhar Tsarnaev into custody on Friday night local time (Saturday afternoon AEST), after finding him in a boat in a Massachusetts neighbourhood.
His older brother was killed earlier Friday in an attempt to escape police.
Obama said there were still many unanswered questions about the bombings, including whether the two men had help from others.
He urged the public to not rush to judgment about their motivations.
The president vowed to find out what turned two young US residents accused of the Boston bombings to hate.
Obama said in his brief on-camera statement that the attacks had failed because Americans refused to be terrorised and heaped praise on police and law enforcement services while remembering the dead and injured.
Celebrations had erupted in Boston and beyond as the capture was announced in a tweet from police.
In the neighbourhood where 19-year-old Dzhokhar Tsarnaev engaged in a firefight with police while hiding out in a parked boat, dozens of people at a police barricade cheered and applauded as police and emergency responders left the scene.
The jubilation was widespread. The mayor of Boston tweeted, "We got him!" And in New York City, at the home of the Mets baseball team, fans leapt to their feet and cheered.
