​Manchester United insist that midfielder Paul Pogba is not for sale despite the Frenchman's public admission over the weekend that he is looking for a "new challenge" this summer.

Pogba joined United three seasons ago, but has been the subject of intense interest from Real Madrid and Juventus in recent weeks. The Italian champions have held meetings about potentially signing the player, while Zinedine Zidane, Los Blancos' coach, has revealed publicly that he would like to sign Pogba on more than one occasion.

​Real Madrid have already spent around €300m this summer - signing players such as Luka Jovic and Eden Hazard - but have now turned their attention to a new creator. Zidane is adamant that it's Pogba he wants, despite Florentino Perez's interest in players such as Christian Eriksen.

Both Madrid and Juve, however, have been put off by United's demands. The public stance from United is that Pogba is not for sale, however it's reported by the Mail that a "gargantuan" offer - perhaps in the region of £150m - would be enough to make them consider a sale.

The problem is, neither club can afford that type of money. Real are not looking to pay any more than €120m, and a number of reports have suggested that each club could put players up for exchange - including the likes of Paulo Dybala and Gareth Bale - in order to help offset the cost, but the interest isn't there on United's side in such a deal happening.

Instead, were they to sell, United are expected to demand a full cash payment which they'd then reinvest. Eriksen was tipped as one option on United's radar, but journalist Tom McDermott reports that the player and his entourage have rejected the suggestion - with the Dane himself holding out for a move abroad.

United, however, are reported in Spain on Monday morning to be monitoring Barcelona pairing Philippe Coutinho and Ivan Rakitic. ​Mundo Deportivo suggest that United have known for months about Pogba's plans to leave, and they have already been preparing for it. Coutinho has already let his Barcelona teammates know that he wishes to go, but his ties to Liverpool - who he left to move to Spain - make a potential deal controversial to say the least.

Rakitic, meanwhile, has always retained that he wishes to stay. He's also a favourite of Ernesto Valverde, the Barça coach, though people above him within the club would consider a sale.

Other players have been linked with ​United - we're probably up within the thousands since the end of the season now, to be honest - but the sale of Pogba (and the money to come from it) would surely leave United with three midfielders to sign - Ander Herrera has already departed and United wanted a midfielder even before then, remember - prior to the window closing on August 8.

Philippe Coutinho,Ivan Rakitic

​Pogba, though, has made his stance clear, saying in Japan on Sunday: “For me I have been for three years in Manchester and have been doing great; some good moments and some bad moments, like everybody. Like everywhere else.

“After this season and everything that happened this season, with my season being my best season as well...I think for me it could be a good time to have a new challenge somewhere else. I am thinking of this: to have a new challenge somewhere else.”