Premier League - United lead race for Ozil
The 21-year-old's contract with Bremen expires next summer and talks over a new deal have broken down, meaning the Bundesliga side are likely to cash in on him this August to avoid losing him for free.
The club's Sporting Director Klaus Allofs said: "We had hoped to reach agreement before the World Cup. But we could not find a solution in our discussions."
United's Premier League rivals Arsenal and Tottenham are also tracking Ozil. Arsene Wenger sees him as the ideal replacement if Cesc Fabregas leaves for Barcelona.
Real Madrid manager Jose Mourinho is also interested in the player, but would rather wait until the end of the season before bringing him to Spain because he will struggle to accommodate both Ozil and Brazilian star Kaka in his starting XI.