Moyes, 50, succeeded Alex Ferguson at the helm of the Premier League side on July 1 but the move quickly became a fiasco with the team slumping to a series of embarrassing defeats.

After feverish speculation in the British media, United confirmed Moyes's departure in a brief statement.

"Manchester United announces that David Moyes has left the club," United said.

"The club would like to place on record its thanks for the hard work, honesty and integrity he brought to the role."

United later confirmed Giggs would fill in on a caretaker basis.

"Following the departure of David Moyes as manager, Manchester United has announced that Ryan Giggs, the club's most decorated player, will assume responsibility for the first team until a permanent appointment can be made," said another statement.

"The club will make no further comment on this process until it is concluded."

Giggs, Britain's most decorated player and United's record appearance-maker, was informed of the news after arriving at United's Carrington training ground near Manchester on Tuesday morning.

His first game in charge will be a league fixture at home to Norwich City on Saturday.

Giggs, 40, made his United debut in March 1991 and has made 962 appearances for the club, winning 13 Premier League titles, two Champions Leagues, four FA Cups, three League Cups and one FIFA Club World Cup.

He has no previous managerial experience, but has combined his role as a player with a position on United's coaching staff since the start of the current campaign.

Experienced Dutch coach Louis van Gaal has emerged as the British bookmakers' favourite to succeed Moyes on a permanent basis.

The 62-year-old, whose previous clubs include Ajax, Barcelona and Bayern Munich, recently expressed a desire to work in England when his contract as manager of the Netherlands expires after this year's World Cup in Brazil.

However, Jurgen Klopp of Borussia Dortmund, another rumoured contender, has already ruled himself out of the running.

Klopp told British newspaper The Guardian: "Man United is a great club and I feel very familiar with their wonderful fans. But my commitment to Borussia Dortmund and the people is not breakable."

- 'Worse and worse' -

Ferguson, British football's most successful manager, personally hand-picked Moyes to succeed him after announcing his retirement last May following 26 and a half trophy-studded years at Old Trafford.

Moyes signed a six-year contract and inherited a team that had romped to the Premier League title -- United's 20th English league crown -- by 11 points, but he endured a torrid season.

United have slumped to seventh place in the league table and been eliminated from both domestic cup competitions and the Champions League.

Moyes's last game in charge was Sunday's 2-0 loss at his former club Everton, which confirmed that United will not compete in the Champions League next season for the first time since 1995.

The defeat, United's 11th of the league campaign, left the defending champions 13 points below the Champions League places and 23 points behind leaders Liverpool.

Moyes's transfer dealings proved equally disappointing, with �27.5 million ($46.2 million, 33.5 million euros) midfielder Marouane Fellaini, signed from Everton, and �37.1 million record signing Juan Mata, who arrived from Chelsea in January, struggling to make an impact.

As a result, United's American owners, the Glazer family, reportedly felt uneasy about the prospect of handing him the funds needed to rebuild the squad during the forthcoming close season.

Former United player Gary Neville, now a television pundit and England coach, said that while he was disappointed by the decision, Moyes's struggles had left the club in a difficult position.

"I think it could have been dealt with a whole lot better," Neville told Sky Sports News.

"I believe in managers being given time. However, there's no disguising that the football this season has been poor and the results have been poor. The performances have got worse and worse."

Andy Mitten, editor of the fanzine 'United We Stand', said the majority of supporters would support the decision to jettison Moyes.

"I don't think there will be many United fans who are too upset by the decision," he told BBC News.

"They know he is a good man, a good football manager, but he wasn't the right manager for Manchester United."