In a statement, the foreign ministry called the recruitment "a violation of Jordanian law and international law" that "exposes citizens to serious danger".

Spokesman for the ministry Fuad al-Majali called on Jordanians "to report any attempts to recruit them into the Russian army" and warned of both legal risks and the danger of death.

The ministry, he said, "has requested the Russian authorities to stop recruiting Jordanians and to terminate the service of any Jordanian citizens already enlisted".

The ministry was also aware of online recruitment efforts, he said.

It is illegal for Jordanians to join the armed forces of a foreign country.

It's unknown how many Jordanians may have been recruited, but hundreds live in Russia and more than 20,000 have studied in the countries of the former Soviet Union, according to unofficial data.

Early in Russia's full-scale invasion of Ukraine, when Moscow was propping up former president Bashar al-Assad's rule in Syria, Russian President Vladimir Putin said he wanted to recruit 16,000 fighters from the Middle East -- with around 2,000 regular Syrian troops later reportedly sent to Russia.