Manchester United are chasing Borussia Dortmund's Robert Lewandowski and Mats Hummels as Sir Alex Ferguson looks to rebuild his side ahead of next season, according to the Daily Mail.
The Red Devils are considered as favourites to sign Dortmund playmaker Shinji Kagawa but have now emerged as contenders for his teammates as well.
Ferguson was in Berlin on Saturday - hours before United's crucial last game of the season - to watch Dortmund's 5-2 win over Bayern Munich in the German Cup final and it is believed that the Scot was monitoring the Bundesliga champions' star trio.
Lewandowski's agent Maik Barthel has revealed that contract negotiations between his player and Dortmund have hit a wall and United are keeping tabs on the striker.
"The offer from Dortmund is not enough and I can confirm there is interest from Manchester United," Barthel said.
The report also says that Hummels's father Hermann, who is the defender's agent as well, has been invited to Old Trafford for talks.
It is believed that United would have to shell out around £50 million to sign all three, but Dortmund managing director Hans-Joachim Watzke has claimed that no player, other than Kagawa, is up for sale.
"We expect Kagawa to go, but no amount of money will persuade us to sell the others," stressed Watzke.
Ferguson congratulated Manchester City after their last gasp victory over QPR on Sunday to win the Premier League title.
United beat Sunderland 1-0 and came agonisingly close to clinching the title before Sergio Aguero pulled off City's winner in injury time.
The Scot congratulated his rivals on their first league win in 44 years and also has claimed that the experience will help United's young players, when they prepare for future campaigns.
"It's a cruel way [to lose], but we've experienced many ups and downs. We've won the title three times on the last day. Congratulations to our neighbours. But these young players will be around in five six, seven years' time. This experience will be good for them," the Telegraph quoted Ferguson as saying.
United finished the season on 89 points - a Premier League record for a team that has not won the title.