West Ham ask for Anthony Martial as part of deal to take defender Issa Diop to Manchester United

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West Ham have laid down their demands to Manchester United and asked for Anthony Martial to be included in a deal for defender Issa Diop. 

United are in the market for a central defender this summer as Ole Gunnar Solskjaer looks to bolster his back line, and have targeted Diop following his impressive debut campaign with the Hammers.

A bid in the region of £40million has been knocked back by West Ham, who are only willing to sell the player if highly-rated winger Martial is involved in the deal.

West Ham want Anthony Martial to be part of any deal involving defender Issa Diop

United have targeted Diop following his impressive debut campaign with the Hammers

Sportsmail understands West Ham are reluctant to sell 22-year-old Diop, who they signed from Toulouse in a club-record £22million deal in June 2018.

Diop became the second signing of manager Manuel Pellegrini and penned a five-year contract with the club. 

Defenders have become a priority for United but it is believed a fee as high as £60m may be what is needed to get Diop to Old Trafford this summer. 

Diop penned a five-year contract with West Ham after joining from Toulouse last summer

Leicester City defender Harry Maguire is another target for United as they seek defenders

Leicester City's Harry Maguire is another player United are interested in but the Foxes are digging their heels in as they seek £90m for the England international - a fee which has put off United's rivals Manchester City. 

Napoli's in-demand defender Kalidou Koulibaly has been another option for some time but is considered too expensive with the Neopolitan side looking for close to £100m.  

Martial has had a difficult time at United since joining the club in 2015 from Monaco. 

Under Jose Mourinho, the Frenchman was often on the bench and there were major questions over his future with talk that he could be sold had the Portuguese boss not been sacked. 

But club chiefs are said to feel that the 23-year-old is worth persisting with and they have no interest in allowing him to depart this summer as they look to build a young, exciting side.   

Martial has had a frustrating career at United but club chiefs feel he is worth holding on to

Ole Gunnar Solskjaer is building a young and exciting team and is keen to keep hold of Martial

Daniel James has already joined for £18m from Swansea City which provides competition for places in wide areas between Martial, Alexis Sanchez and Jesse Lingard, with Marcus Rashford tipped to be the first-choice No 9.

Another Frenchman who United are keen to keep hold of is Paul Pogba.

The midfielder caused a whirlwind over the weekend when the Real Madrid target suggested now is the right time for him to take on a new challenge. 

Sportsmail exclusively revealed on Monday night that United are prepared to offer him a new mega-money contract iworth £500,000-a-week n a bid to persuade their unsettled star to stay.

Pogba scored 16 goals and added a further 11 assists last season and United are determined to keep their record signing next season. 

The club could only entertain the idea of selling him if they receive an offer well in excess of the £89m they paid Juventus for him in 2016. 

Another Frenchman that United want to keep this summer is central midfielder Paul Pogba 

United chief Ed Woodward is adamant that Pogba's commercial potential be kept at the club