Manchester United have pulled out of their proposed £10m move to sign the young Partizan Belgrade playmaker Adem Ljajic, prompting claims from the selling club's president that financial problems may lie behind the decision.

The Partizan president, Dragan Djuric, said in the Serbian media yesterday that the failure to seal the deal under which 18-year-old Ljajic was to follow former team-mate Zoran Tosic to Old Trafford reflected the fact that “maybe the real problem is that Manchester United is in financial crisis.”

United quickly and robustly dismissed that suggestion, insisting that they had not taken up the option to buy the player which they had announced when Tosic arrived last January, because they have spent 12 months monitoring the player and remain unconvinced that he will flourish at Old Trafford.

United have always rejected suggestions that the decision to bank, rather than spend, most of the £80m revenue for Cristiano Ronaldo was to do with the club's £700m debt.

United also said that they had better young players emerging through their own ranks than Ljajic, which suggests they are relying on the 20-year-old French winger Gabriel Obertan to be the face of the future with Antonio Valencia on the flanks.

The failure of Nani to step up since the departure of Ronaldo has certainly left work to do in that department.

There had been a feeling in Belgrade for several days that the Ljajic deal might be falling away as United stalled on securing the necessary work permit. The player's agent Mladen Furtula said on Tuesday that he was “confident that everything will be OK and that from January Ljajic be officially Manchester United's.”

Ljajic has been undergoing a separate training programme from the rest of the Partizan players, in readiness for the rigours of the Premier League.

The decision not to take up the option to buy will come as a blow to supporters, since Ljajic was always considered the more promising of the two Belgrade wingers who were to be joining the club in a joint £16.3m deal.

Tosic has sunk without trace. Though the United manager, Sir Alex Ferguson, suggested last January that Tosic might be a part of things by the end of the season, the player has proved too slight to make an impact and his contributions have been limited to five League Cup games, the most recent an eight-minute appearance in the 2-0 win over Tottenham on Tuesday night.

The question of how the club might now recoup some of their £7m investment in Tosic is difficult, given that no Serbian club is likely to be able to afford that sum.