PARIS — The French newspaper Le Monde is reporting that Saudi Arabia wants France to help prevent Qatar from buying Russia's most advanced air defense missile system.

Le Monde said it has seen a letter written by Saudi King Salman to French President Emmanuel Macron to express his "deep concerns" that Qatar is looking to purchase the air defense system, the S-400.

Le Monde quoted the letter as saying that if the missiles were deployed in Qatari territory, "the kingdom would be ready to take all necessary measures to eliminate this defense system, including military action."

King Salman signed an agreement in Moscow last year to purchase the S-400 air defense system.

Saudi Arabia and other Arab neighbors have been embroiled in a diplomatic standoff with Qatar since last year, claiming it funds terrorism, which it denies.

Le Monde says the king ended the letter asking Macron for his assistance in preventing the sale.

The French president's office said Sunday it wouldn't comment on Le Monde's report.