Talks over a new West Ham United contract for Reece Oxford have stalled, alerting Manchester United and Manchester City, sources close to the player have told ESPN FC.
West Ham have been in talks with Oxford over a new deal for several months, but the parties have been unable to agree terms on a contract extension for the teenager.
The 17-year-old has 18 months left on his current deal and West Ham risk losing one of their prized assets on the cheap if a breakthrough is not made.
Oxford broke into the West Ham first team at the start of last season, becoming the club's youngest ever player when he made his debut at the age of 16 years and 198 days in the Europa League qualifying tie with FC Lusitanos last July.