Boston Marathon bomb suspect Dzhokhar Tsarnaev has been captured by police after being located in a boat in the back garden of a home in the Watertown area of the city.
The 19-year-old, who was spotted by a resident at the home, was taken into custody following an hour-long gunfire standoff and driven to Massachusetts State Hospital, where he is in a serious condition.
President Barack Obama has said authorities who hunted down the suspect had "closed an important chapter in this tragedy" with his capture.
One Watertown resident summed up the mood on the street as people who had been locked indoors for the past day in fear ventured outside in the darkness to rejoice at the manhunt's successful conclusion.
Loud cheering at the authorities soon broke out in the Boston district after the capture was announced, while emergency services who previously had the area on lockdown sounded their horns in response.
Police later confirmed Dzhokhar Tsarnaev was captured after a resident spotted blood on the covered boat in his garden.
A law enforcement official confirmed the homeowner glimpsed the 19-year-old in the boat, retreated and called the authorities.
Police established a perimeter around the boat and exchanged gunfire with Tsarnaev over the course of the next hour.
A hostage rescue team and the FBI made entry into the boat and removed the suspect, who was still alive, and took him to Boston Beth Israel Deaconess Hospital.
Boston Police soon celebrated the completion of the hunt for the surviving main suspect after Monday's bombings, which killed three people and injured more than 170 in two blasts at the end of the famed city race.
CAPTURED!!! The hunt is over. The search is done. The terror is over. And justice has won. Suspect in custody.
Boston mayor Tom Menino merely tweeted:
He later issued a multitude of thanks following the successful conclusion to the manhunt.
Colonel Timothy Alben of Massachussets Police said his force was "so grateful" to bring "justice" to their case.
The dramatic development came barely hours after search police had admitted all leads towards finding the younger Tsarnaev had proven fruitless, despite a vast sweep of homes in Watertown.
The teenager had been on the run after fleeing the scene of a shootout with police last night in which his elder brother and fellow suspect Tamerlan Tsarnaev was killed.
A police officer was killed in the exchange of fire at Massachusetts Institute of Technology (MIT).
The brothers had been wanted for questioning after being identified as the main suspects from CCTV footage captured in the build-up to Monday's twin bombing in the city centre.
President Obama has said there are "still many unanswered questions" following the capture of the second suspect.
– PRESIDENT OBAMA
Among them: why did young men who grew up and studied here as part of our communities and country resort to such violence?
How did they plan and carry out these attacks?
And did they receive any help?
He urged the public not to rush to judgement at Dzhokhar Tsarnaev and his brother's alleged motivations, despite also branding them "terrorists".
"It's important that we do this right," Mr Obama said at the White House, warning against the danger of jumping to conclusions and spreading rumours in the age of social media.
The mother of the two suspects Zubeidat Tsarnaeva has said the incident is a 'set up':