Both players are expected to be unveiled by their new clubs today after agreeing terms and undergoing medicals.
But they require work permits and the correct papers to complete their moves.
Manchester United and Arsenal are waiting on the papers being signed off before they can be official.
Sanchez is set to pocket £500,000 a week at United after heading up to Manchester over the weekend.
He was spotted taking a selfie at Old Trafford wearing the No 7 shirt.
Mkhitaryan meanwhile has been spotted in London as he sorts out his move to Arsenal.
Sanchez was in Manchester this morning and was seen leaving the Lowry after meeting Sir Alex Ferguson.
But he is still to have the move confirmed with a paperwork hold up.
However the formalties are expected to be complete this afternoon and the moves announced shorly after.
Jose Mourinho said on Saturday: “I expect soon or never. I think it’s so close, so close, so close that if it doesn’t happen, it’s not going to happen, so I am positive.
“I know that my people are doing absolutely everything they can – the owners with the green light and Mr Woodward working hard.
“I think everybody is giving everything they can and I think we’re going to be successful.”
