Al-Qaeda leader Osama bin Laden is killed following a firefight with US troops in Pakistan. But International Editor Lindsey Hilsum questions how significant his death will be for the war on terror.
Bin Laden was holed up in a two-storey mansion, surrounded by 5.5 metre-high walls, just 100 metres away from a Pakistani army base in Abbottabad and about 80km from the capital Islamabad.
Mr Obama said: “The death of bin Laden marks the most significant acheivement to date in our nation’s effort to deal with al-Qaeda.”
He revealed the dramatic development in a televised address at the White House in Washington. Crowds gathered outside to celebrate, chanting pro-US slogans.
"Osama bin Laden's killing has huge symbolic value for President Obama, and may lift his approval ratings amongst American voters," writes Lindsey Hilsum.
"It's tempting to see it as a bookend to the decade of terror which started on 9/11. Now, from Egypt to Libya, Syria and beyond, Arab youth are fighting for freedom and democracy, not for an extremist version of Islam. But it may not be so simple."
Read Lindsey's World News blog - Bin Laden's death: Will it make any difference?
Mr Obama added: “The fight against terror goes on, but America has sent an unmistakable message: No matter how long it takes, justice will be done.”
There have also been celebrations at ground zero, the site of the World Trade Center, in New York.
An eyewitness in Abbottabad, who only wanted to be referred to by his first name Saifullah, told Channel 4 News: “I first heard the helicopters at around 1 o’clock: they were moving from one place to another like they were searching for something in the town. Soon after, there was a huge blast…
“When anyone sees the movements of helicopters, one can guess that something very serious is going on. No one was believing that there would be any type of blast in Abbottabad: it’s a quite a peaceful place. In the history of Pakistan there’s not been a single blast here, so we didn’t expect any blast so we were shocked by that.
“The compound is not in the main [part of town]: it’s on the side of the town and its not a residential area; it was in the farm area. On its side is a lot of fields so no one goes there: there are no shops, no movement; no-one could have guessed there was something happening there.”
It is a decade since the 9/11 atrocities which bin Laden was accused of orchestrating. Nearly 3,000 people died when hijacked planes were flown into the Twin Towers and the Pentagon. Another plane crashed in Pennsylvania.
David Cameron said the death would “bring great relief to people across the world”.
Channel 4 News special report: War on Terror
Osama bin Laden’s fortified compound was just 100 metres from the Pakistani military academy.
A source familiar with the US operation said bin Laden was shot in the head. Although it had been a “kill” operation, officials said that bin Laden had only been shot after attempting to resist the raid.
DNA tests were used to confirm that the body was that of Osama bin Laden, before he was, say US defence officials, given a religious funeral and was then buried at sea.
It is believed this was to avoid creating a “shrine” for his followers.
A US official said Pakistani authorities were told the details of the raid after it had taken place. President Obama said US forces led a targeted operation that killed bin Laden in the swoop on Abbotabad. No Americans were killed and they took care to avoid civilian casualties, he said.
More from Channel 4 News: Pakistan drone warfare
Bin Laden and three adult men, including a son, were killed along with his wife who was used as a shield by a male combatant, officials said.
A US helicopter was lost due to a mechanical problem and its crew and assault force safely evacuated.
The operation was monitored in real-time by CIA Director Leon Panetta and other intelligence officials in a conference room at CIA headquarters in Langley, Virginia. The Us president also watched minute-by-minute developments via videolink.
Obama may perhaps now find it easier to wind down the nearly decade-old war in Afghanistan. But the operation could complicate relations with Pakistan, already frayed over US drone strikes in the west of the country and the jailing of a CIA contractor accused of killing two Pakistani men.