Police are working to establish the motive behind a mass shooting which left 59 people dead and another 527 injured at a Las Vegas concert.
Gunman Stephen Paddock, 64, opened fire from the 32nd floor of the Mandalay Bay Hotel towards an open-air music festival on Sunday evening.
Police found 23 guns in his hotel room, as well as firearms and explosives at his Nevada home.
But as yet, no clear reason for the killing has emerged.
Investigators have found no link to international terrorism, despite a claim from so-called Islamic State (IS). Some investigators have suggested Paddock had a history of mental illness, but there is no confirmation of this.
Paddock had no criminal record and was not known to police.
In his latest comment on the shootings, President Donald Trump said he would be "talking about gun laws as times goes by".
Speaking to reporters at the White House, he gave no further detail on the gun laws issue.
Mr Trump described the gunman as a "very, very sick individual".
What do we know of the gunman?
Stephen Paddock, a former accountant with a big gambling habit, lived in a community of senior citizens in the small town of Mesquite, north-east of Las Vegas.
He reportedly lived with a woman called Marilou Danley who was out of the country in Japan and did not appear to be involved in the shootings, police said.
Las Vegas Sheriff Joseph Lombardo said that when police searched the property after the attack, they found 19 "additional firearms, some explosives and several thousand rounds of ammo, along with some electronic devices we're evaluating at this point".
Officers also found ammonium nitrate in Paddock's car.
David Famiglietti of the New Frontier Armory told the BBC that Paddock had purchased firearms at his store in North Las Vegas in the spring of this year, meeting all state and federal requirements, including an FBI background check.
However, the shotgun and rifle Paddock bought would not have been "capable of what we've seen and heard in the video without modification", Mr Famiglietti said.
The fast shooting rate audible in recordings of Sunday night's attack indicates that Paddock may have modified his guns with legal accessories to make them fire at speeds approaching those of automatic weapons.
Despite the large cache of weapons found in the killer's home, his brother, Eric, is struggling to accept that he acted in this way.
He said he was "in shock, horrified, completely dumbfounded".
IS has claimed to be behind the attack, saying Paddock had converted to Islam some months ago.
But the group provided no evidence for this and has made unsubstantiated claims in the past.
The IS claim of responsibility for the Las Vegas attack is very unusual in that the perpetrator's profile does not fit that of supporters or "soldiers" that the group has claimed in the past, writes Mina al-Lami, who monitors jihadist groups for the BBC.
The FBI said it had found "no connection to an international terrorist organisation".
How did the attack unfold?
The final shows of the three-day Route 91 country music festival were in full swing when the gunman struck.
According to police, Paddock had booked into the hotel four days earlier, on 28 September, reportedly using some of Ms Danley's identity documents.
Sheriff Lombardo said there were 10 suitcases in the suite, which had two rooms.
Thousands were enjoying a performance by top-billing singer Jason Aldean when the first of several bursts of automatic gunfire rang out - hundreds of shots, witnesses say. That was late on Sunday night - 22:08 local time (05:08 GMT on Monday).
Hundreds of concert-goers scrambled for cover, flattening themselves against the ground, rushing for the exits or helping others to escape as Paddock sprayed the site from his high vantage point.
It is thought he moved between two windows in his suite as he carried out the attack.
"One man had blood all over him and that's when I knew something was seriously wrong," Mike Thompson from London told the BBC.
"People were running and there was chaos."
Many hotels on the Las Vegas strip close to the scene were placed on police lockdown and parts of Las Vegas Boulevard were shut.
Who are the victims?
The authorities have yet to confirm the identities of any of those killed. But many have been identified by family members and in local media.
They include a 29-year-old nurse who was shot in the back while he tried to save his wife, a Navy veteran who had just returned from a tour of Afghanistan, and an off-duty police officer who also coached youth football.
What gun laws does Nevada have?
Nevada has some of the least stringent gun laws in the United States.
People are allowed to carry weapons and do not have to register themselves as gun owners.
Background checks are done when people buy guns, but they are also allowed to sell them privately.
Former congresswoman Gabrielle Giffords, who survived a shooting six years ago, called for political leaders in Washington to introduce tougher gun laws following the Las Vegas attack.
Her husband Mark Kelly read out a joint statement from the couple on the steps of the Capitol, saying thoughts and prayers from the White House were not enough to stop the next shooting.
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