Tottenham defender Toby Alderweireld and Chelsea midfielder Willian are on a list of summer transfer target for Manchester United, a source close to the Old Trafford club has told Yahoo Sport UK.

United manager Jose Mourinho has confirmed that he is already planning to make additions to his squad ahead of next season, with persistent reports linking him with a move to Atletico Madrid striker Antoine Griezmann cooling after the player confirmed he is in no rush to leave Spain.

Now it has emerged that Mourinho is keen to add players to his squad who boast Premier League experience, as he is keen to avoid the kind of acclimatisation period newcomers to English football tend to require.

Paul Pogba and Henrikh Mkhitaryan both took time to find their feet in the Premier League after high profile summer moves, with Mourinho keen to sign players this summer that are accustomed to the unique demands of the competitive English league in a bid to launch a title challenge from the opening day of next season.

READ MORE: Five stars to keep an eye on this international week

READ MORE: Thibaut Courtois brushes off Real Madrid transfer talk

The capture of Alderweireld would appear to be challenging, with the Belgian defender currently in talks with Spurs over a new contract that will remove the £25m release clause in the contract he signed when he joined the club from Atletico Madrid in the summer of 2015.

However, Tottenham may have been a little concerned by Alderweireld’s reaction in a recent interview, as he appeared to side-step questions over his future.

“I signed for Tottenham for a reason and I love to play here,” Alderweireld said. “I see no problem. Whatever has been written, I am only focusing on football because that is what I love to do.”

Former Arsenal defender Matthew Upson is among those urging Tottenham to sign up their 28-year-old centre-back to a new deal, as he suggested all the top clubs in England would be keen to sign him if he shows any inclination to join a club that could double his weekly wages.

United’s links will Willian are inevitable after Mourinho tried and failed to sign the one player who shone for him during his miserable final few months as Chelsea manager last season.

While Eden Hazard, Cesc Fabregas and Diego Costa were dramatically below their best as Chelsea’s title defence collapsed in alarming fashion, Brazilian midfielder Willian continued to give his all to the cause as he carried the Blues during the first half of last season.

However, he has become something of a bit-part player since Antonio Conte took over as Chelsea manager, starting just 13 Premier League games so far this season and now Mourinho is set to try and sign the 28-year-old once again.

“There were enquiries, yes. It was from Manchester United, because Mourinho is there too,” Willian told Globo Esporte when quizzed on the interest from United last summer.

“From other clubs I don’t know but there are always some things on the internet. I’m glad to hear that there are clubs that admire my work.”

Mourinho went out of his way to exchange a handshake with Willian during the feisty FA Cup quarter-final against Chelsea and he is now keen to step up his interest in the winger with Ashley Young and Wayne Rooney certain to free up space in United’s attacking line when they leave the club at the end of this season.

Meanwhile, United are still waiting to hear whether Zlatan Ibrahimovic will commit to a new one-year contract, with the possibility of a clause that will allow either side to trigger an additional one-year extension to a new deal believed to be under discussion.

Ibrahimovic is also being courted by Major League Soccer side LA Galaxy, but he is keen to finish his career on a high and has thrived in a first season at United that has seen the 35-year-old bag 26 goals so far.

“I could have moved to China and play without too many problems but I accepted this challenge. I’m training every day, I like working hard,” he said in an interview with Fox Sports Italia last weekend.

READ MORE: Leicester striker received death threats after Ranieri sacking

READ MORE: Arsenal players want Arsene Wenger to stay – Giroud

READ MORE: ‘Ban mid-season sackings’ says Gary Neville

READ MORE: Neymar admits he would like to play in the Premier League

“I signed a one-year deal with option for another one but I haven’t got much time left. I still want to have fun and I still want to make the difference. I don’t know what will happen, let’s see.

“I don’t want to retire when I’ll be struggling. I want to retire when I’m still at the top. I’m happy now but I don’t know what could happen in the future.”

Even though United have plenty of targets to focus on in the coming weeks in both the Premier League and Europa League, it appears planning is already well underway for what Mourinho will hope is a sustained title challenge and a return to the Champions League next season.