Luton have made their ninth summer signing following the arrival of winger Danny Green.
Notts County have signed Togo international Mawouna Amevor on a two-year deal.
Mark Hughes has been sacked as manager of QPR after failing to win any of their opening 12 Barclays Premier League fixtures this season.
Despite votes of confidence to the contrary, there had been mounting speculation that Hughes was coming under increasing pressure from owner Tony Fernandes and the QPR board, especially following last weekend's 3-1 home defeat to fellow strugglers Southampton.
The club refuted suggestions the Welshman had refused to budge after being asked to resign in a meeting at the club's training ground on Monday evening.
But now they have issued a statement confirming the 49-year-old, who took over at Loftus Road in January, has had his contract terminated.
The statement read: "Queens Park Rangers Football Club has today (Friday) terminated the contract of manager Mark Hughes with immediate effect.
"This decision has been taken after careful consideration by the Board of Directors, following numerous meetings over the last few days.
"The Board of Directors wish to thank Mark for his commitment, hard work and dedication in his 10 months in charge. Mark has shown integrity and professionalism throughout his time here, but ultimately the circumstances we find ourselves in have left the Board of Directors with very little choice but to make a change."
The sacking comes just 24 hours before QPR travel to face Manchester United at Old Trafford and the club confirmed they are looking at appointing a new manager as soon as possible.
"The Board will now be working actively to put a new managerial structure in place as soon as possible," the statement continued.
"Mark Bowen and Eddie Niedzwiecki will take charge of the R's trip to Manchester United in the Barclays Premier League on Saturday afternoon.
"The club will be making a further announcement in due course."
Rangers then cancelled their pre-match media conference which was scheduled for Friday afternoon.
Fernandes, who backed Hughes significantly in the transfer market over the summer, had continually taken to Twitter following recent bad results to voice his support for the manager.
But the derision among the crowd at Loftus Road during the 3-1 loss to Southampton suggested Hughes had lost the backing of the majority of Rangers' fans.
Crisis talks were held at the club's Harlington training base on Monday evening but Hughes continued as manager, preparing his side for the tough test at Old Trafford this weekend.
But the decision was taken by the board to end Hughes' tenure as boss with the board aware that any increase in the five-point gap between QPR and Reading in 17th would make it harder to find a new boss to take charge.
Mark Hughes factfile:
1963: Born Wrexham on November 1.
1980: Signs professional terms with Manchester United.
1983: Makes debut for United against Oxford.
1984: Scores on international debut for Wales against England.
1985: May - Wins FA Cup winner's medal as United beat Everton.
1986: Joins Barcelona in a £2.3million deal. Fails to settle, however, and is loaned out to Bayern Munich.
1988: Signs again for Manchester United for £1.8million.
1991: May: Scores twice against Barcelona as United win European Cup Winners' Cup.
1993: In the United side that wins inaugural Premiership title.
1994: United win the league and FA Cup double with Hughes a pivotal part of the side.
1995: Signs for Chelsea for £1.5million.
1997: Wins fourth FA Cup winner's medal after Chelsea beat Middlesbrough 2-0.
1998: Wins second European Cup Winners' Cup medal with Chelsea. Moves to Southampton before start of 1998-99 season.
1999: Appointed Wales manager for the last two European Championship qualifiers.
November 25 - Agrees four-and-a-half-year deal as Wales manager, the first 18 months of which is to be served on a part-time basis.
2000: March 14 - Joins Everton on a 14-month deal, scoring one goal in 15 appearances.
October 24 - Joins Blackburn on a free transfer, helping them to secure promotion to the Premiership.
2001: June - Wales fail to qualify for 2002 World Cup after winning just two of their last 12 games.
Scores two goals in 25 appearances as Rovers maintain their top-flight status and win the Worthington Cup and a place in Europe.
2002: May 13 - Told his contract will not be renewed by Blackburn and retires at the age of 38.
2003: Wales guarantee themselves a Euro 2004 qualifying play-off place after a 1-1 draw with Finland. They are beaten by Russia in play-off but Hughes insists he wants to stay in charge.
September 15 - Named manager of Blackburn.
2005-06: Blackburn finish sixth and qualify for the UEFA Cup.
2007: Blackburn return to the UEFA Cup, but are surprisingly beaten 3-2 on aggregate by Greek side Larissa in the first round.
2008: June 4 - Appointed as Manchester City manager on a three-year contract.
September 1 - Abu Dhabi United Group reach a takeover agreement with City, making the club the richest in world football. The new owners announce they want a top-four finish. City outbid Chelsea to sign Real Madrid forward Robinho in a British record £32.5million deal.
2009: January 3 - City suffer humiliating FA Cup third-round defeat, losing 3-0 at home to Championship strugglers Nottingham Forest.
May 24 - City finish 10th in the Barclays Premier League in Hughes' first season in charge.
July - The £12m capture of Gareth Barry from Aston Villa sparks a multi-million pound spending spree, which also saw acquisitions including Roque Santa Cruz, Emmanuel Adebayor, Kolo Toure, Carlos Tevez and Joleon Lescott.
November - Pressure mounts on Hughes following City's run of seven straight Barclays Premier League draws.
December 19 - City terminate Hughes' contract, despite a 4-3 defeat of Sunderland. Roberto Mancini is immediately installed as his successor.
2010: July 29 - Appointed manager of Fulham on a two-year contract.
2011: May - Fulham finish eighth in the Premier League and qualify for the Europa League via the fair play league.
June 2 - Quits as Fulham manager.
2012: January 10 - Appointed QPR manager on a two-and-a-half-year contract.
May - Keeps QPR in the Premier League despite suffering a 3-2 defeat to Man City on the last day of the 2011/12 season.
July/August - Embarks on a signing spree, bringing in the likes of Robert Green, Park Ji-Sung, Julio Cesar and Esteban Granero.
November 4 - A 1-1 draw with Reading extends QPR's winless start to the 2012/13 campaign to 10 matches.
November 17 - A 3-1 home defeat by relegation rivals Southampton increases the pressure on Hughes.
November 23 - Sacked by QPR on the eve of their clash with Manchester United.