Sakho’s agent, Tim Hager, says the 19-year-old is being eyed by the two clubs.
Hager told Sport: “He will be moving clubs this summer. Arsenal are interested, but the club are too cheap at the moment.
“Yes, I think a transfer will happen soon. He wants to play football in England and Arsenal are a good club but Manchester United is a better club.
“Arsenal want him, but Manchester United not yet. Barcelona in Spain, and Bayern Munich in the German league are also interested. They are all the teams at the moment that are interested in the player.
“But the most interested club is Arsenal, they want him the most. Bayern Munich is a top European club, so I think it will be Bayern or Arsenal.”