Arsenal have made a £20million bid for Wayne Rooney, the Mirror reports.
The Gunners have fired the first shot in a war that is sure to spark a response from Chelsea.
Jose Mourinho has Rooney at the top of his Chelsea wish-list, and is expected to make a counter-bid in an effort beat Arsenal for the signature of the 27-year-old.
But senior United sources last night insisted that Rooney is not for sale.
New United boss David Moyes will meet Rooney this week to discuss the Arsenal bid and his future. United decide whether to sell Rooney to a Premier League rival - or hope that clubs like Paris St Germain and Monaco make a bid.
Rooney has two years left on his £250,000-a-week deal and any new offer would have to include a testimonial given that he is approaching a decade of service with the champions.
But first Rooney wants assurances from Moyes about his role in the United team.