Nigeria have threatened to report Newcastle and Chelsea to Fifa if they do not release their players for Tuesday's friendly against Ghana. Newcastle manager Glenn Roeder says Obafemi Martins is tired while Chelsea say Mikel Jon Obi has a thigh injury.

But Nigeria Football Association (NFA) vice-chairman Amanze Uchegbulam told BBC Sport: "This is a friendly on a Fifa approved date.

Newcastle manager Glenn Roeder says Obafemi Martins is tired while Chelsea say Mikel Jon Obi has a thigh injury.

But Nigeria Football Association (NFA) vice-chairman Amanze Uchegbulam told BBC Sport: "This is a friendly on a Fifa approved date.

"Therefore we have the rights to our players on Tuesday."

Uchegbulam has made it clear that the Nigerian FA will report both clubs if they do not release their respective players.

"The excuse being given is that the players are injured," added Uchegbulam.

"Even if that is the case Fifa regulations say that the players should report to their national team for assessment by the national team doctors.

"Until our medical team declare any player unfit we insist that we will report any club that fails to release our players.

"We think it is unfair to Nigeria and in the interest of the good relationship we have with these clubs our players should be released immediately."

Newcastle were hoping to persuade Martins to put club before country as they face Liverpool in the Premiership on Saturday.

Roeder is asking his 10-goal leading scorer not to play knowing an injury could severely affect his club.

"It is only a friendly and Nigeria cannot insist on Oba playing, and because he has had so much football this season, I will be asking him not to play against Ghana," Roeder said last week.

"He has already played nearly 30 games for us - he has probably played more matches this season than at any time in his career.

"He is a great lad and I am sure he will understand the situation because we are a bit thin on the ground for strikers and we do not want the risk of losing him."

Chelsea boss Jose Mourinho said Mikel picked up an injury in the 1-0 win over Charlton.

"A young kid of 19, playing five consecutive matches, running 12 kilometres a game, of course the boy is a little tired and he felt a little pain," said Mourinho.

"We have to scan it, but experience says he has a little muscular problem and for the next 15 days, he is out of competition."