It is believed most of the formalities have now been finalised with the renewal of work permits one of the last issues to be resolved before the transfers of both players are completed.

Footage of Sanchez, 29, outside the Home Office building in Liverpool emerged online on Monday afternoon. The Chile forward would have travelled there to update his work permit with details of his new employer. Mkhitaryan visited the same office.

Reports suggest Sanchez will earn close to £500,000 (€570,000) per week at Old Trafford, including bonuses and image rights.

United moved for the forward earlier this month when it became clear he wanted to leave Arsenal during the current transfer window rather than wait until he came out of contract in the summer.

Prior to that he had been expected to join Manchester City, who had a deal worth up to £60m (€68m) accepted for Sanchez last August but could not complete a deal on transfer deadline day.

City considered bidding again in January but pulled out last week due to the rising costs involved. The Premier League leaders did not want to pay a fee of more than £20m (€23m) while United were not only willing to meet Arsenal’s £35m (€40m) asking price, but offer much higher wages.

The fee has since been cancelled out by United’s willingness to trade Mkhitaryan, who is valued at the same price, in a straight-swap deal.

Sanchez has scored 80 goals in 166 appearances since joining Arsenal from Barcelona in 2014.

Mkhitaryan, 29, has played 63 times for United after arriving from Borussia Dortmund in 2016, scoring 13 goals, although he has recently struggled for game time under Jose Mourinho.

Speaking on Saturday, United boss Mourinho said the deal was "so close" while Arsenal counterpart Arsene Wenger claimed "in the next 48 hours it will be decided one way or the other".

- PA