Paris Saint-Germain have given Saudi club Al Hilal permission to speak to Kylian Mbappe after tabling a world record 300-million-euro ($333 million) bid, a source close to the negotiations told AFP on Monday.

The Riyadh-based club has made a formal offer by letter, the source said, but such a transfer could only be made with the agreement of Mbappe who has never expressed an interest in moving to the fast-growing Saudi league.

"The club has given permission to Al Hilal to speak with Mbappe. That's the request of the letter and that's been granted," the source said.

Mbappe has one year left on his contract with PSG, who want him to leave now rather than for nothing next summer.

But Mbappe, 24, is refusing to sign a new contract and the French champions believe he has already struck a deal to move to Real Madrid next year.

The source said Real Madrid were among a group of clubs which had also expressed an interest in Mbappe.

"In the group so far that have expressed their interest there are Manchester United, Inter Milan, Barcelona, Tottenham and obviously the Saudi club and Real Madrid," the source said.