Wales football manager Gary Speed has died at the age of 42.
Sources have said Speed, the national manager for nearly a year, was found hanged.
Cheshire Police confirmed he was found dead at 07:08 GMT at his home in Huntington, Chester. They said there were no suspicious circumstances.
Former Wales team mate Ryan Giggs said: "Words cannot begin to describe how sad I feel at hearing this awful news."
He said: "Our thoughts are with his family at what must be a very difficult time for them."
The FAW said: "We extend our sympathies and condolences to the family.
"We ask that everyone respects the family's privacy at this very sad time."
The FAW added: "That this tragedy should have overtaken someone so young and talented is a huge loss not only for his family and friends but a nation as a whole."
Speed, who was awarded the MBE in the 2010 Birthday Honours, leaves a wife and two children.
Phil Pritchard, FAW president, said they would do "whatever we can" to help Speed's family.
In a statement, Cheshire Police said: "At 7.08am on Sunday 27th November Cheshire Police was informed of a sudden death at an address in Huntington in Chester.
"Officers went to the scene where a 42-year-old man was found dead.
"The next of kin have been informed and have confirmed the identity of the man as Gary Speed.
"There are no suspicious circumstances surrounding the death and the family have requested that they are left in peace to grieve at this difficult time."
Police said a family tribute will be issued later.
Speed had appeared on BBC1's Football Focus show on Saturday afternoon, just hours before his death.
Footballers, celebrities and politicians began issuing tributes within minutes of the news.
Former Wales team mate, Robbie Savage, Tweeted: "The world has lost a great man in Gary speed I'm devastated spoke to him yesterday morning why ! Why. Why !! I'll miss him so much x
"He come to watch strictly 3/4 weeks ago I high fived him in the front row he loved the show ,he loved life he loved his family ! Devastated".
Former Wales team mate Ryan Giggs said: "I am totally devastated. Gary Speed was one of the nicest men in football and someone I am honoured to call a team-mate and friend.
"Words cannot begin to describe how sad I feel at hearing this awful news. It goes without saying my thoughts are with his family at this tremendously sad time."
First Minister Carwyn Jones said: "I'm deeply saddened to hear about the death of Gary Speed.
"This is devastating news and our thoughts are with his family at what must be a very difficult time for them."
Welsh Secretary Cheryl Gillan tweeted: "This is a sad day for football and for everyone in Wales.
"Gary Speed served club and country as a player and manager with great distinction."
Andrew RT Davies, Welsh Conservatives leader, said: "Gary Speed was tremendously gifted and I - along with millions of others - will always remember him as a legend in the game of football."
'Never be forgotten'
Welsh Liberal Democrats leader, Kirsty Williams, said: "It is a terrible, terrible shock. A tragedy for the Speed family and a tragedy for Welsh football."
Plaid Cymru leader Ieuan Wyn Jones said the "whole nation is in shock", adding: "He will never be forgotten."
At the Liberty Stadium in Swansea - where the home side were playing Aston Villa a minute's silence followed by a minute's applause was held.
Speed, born in Mancot, Flintshire, took over the Wales job in December 2010, and earlier this month, said the side's rapid improvement had exceeded all expectations.
A 4-1 friendly win over Norway represented a third successive win for Wales, and Speed's fifth in 10 games as manager.
At the time, he said: "We've progressed further than I'd have thought in this space of time but we've still got a lot of work to do."
'Stunned and saddened'
Speed won 85 caps for his country during a 14-year international career.
He was given the top job in Welsh football despite only having four months managerial experience.
Speed began his playing career at Leeds United after coming through the trainee ranks, and was part of the side that won the last Football League title in 1992, before the introduction of the Premier League.
A Leeds spokesman said the club was "stunned and saddened" by the news.
He was handed his Wales debut as a 20-year-old in the 1-0 friendly win over Costa Rica in May 1990.
He left Leeds in 1996 after 312 appearances to join Everton - who he went on to captain - in a £3.5m move.
Newcastle followed, in a £5.5m switch in 1998. During his six years with the Magpies, he suffered two FA Cup final defeats, but enjoyed a taste of Champions League football.
He then spent four years with Bolton Wanderers after agreeing a £750,000 move.
Speed became the first player to reach 500 Premier League appearances.
He retired from international duty in 2004, having scored seven goals and captaining his country 44 times.
Speed's final appearance came in 3-2 World Cup qualifying defeat by Poland in October 2004.
His tally of 85 caps is a record for an outfield player.