Nigeria's foreign ministry has issued an urgent warning over what it describes as the increasing illegal recruitment of its citizens to fight in foreign conflicts.

It comes after Ukrainian officials said they found the bodies of two Nigerians who they said were killed in combat last year.

Nigeria has not confirmed those deaths but in a statement on Sunday, foreign ministry spokesperson Kimiebi Imomotimi Ebienfa revealed that "several Nigerians who have fallen victim to such unfortunate situations were deployed to combat zones after being misled and coerced into signing military service contracts".

Kenya has issued a similar warning to its citizens.

According to Nigerian officials, investigations and security reports indicate that some nationals were enticed with promises of well-paid employment, security work, educational opportunities or migration incentives, only to find themselves thrust into active war zones.

In some cases, victims were allegedly forced to sign contracts written in foreign languages without proper legal advice, and their travel documents were confiscated upon arrival.

Intermediaries are also said to arrange travel using tourist or other non-military visas.

Ebienfa cautioned Nigerians against accepting such offers, emphasising that they not only endanger lives but may also violate Nigerian and international laws concerning mercenary activities and foreign enlistment.

The Nigerian government stated it was working with local and international partners to investigate these cases and enhance public awareness.

Its diplomatic missions abroad have been directed to strengthen consular support and issue advisories to citizens.

Ukrainian intelligence estimates that more than 1,400 individuals from 36 African countries have been recruited to fight for Russia. Ukraine itself has previously faced criticism for attempting to recruit foreign nationals, including Africans, to fight on its side.

African governments have increasingly been warning their citizens and working to repatriate those who were deceived into joining the conflict.

Last week, South Africa announced that Russian President Vladimir Putin had pledged assistance in returning South African nationals who had travelled to Ukraine to join Russian forces.

Retired Nigerian military expert Maj Bashir Galma told the BBC that the recruitment of Nigerians and other Africans into foreign conflicts was not unprecedented.

"Even during the Yugoslavia issues many years ago, we had that problem and it is sad that our youth are falling into these traps and losing their lives to a war that means nothing to them," he said.