KARACHI, Pakistan

Pakistan on Thursday turned back a Greek chartered plane carrying alleged illegal immigrants amid a diplomatic standoff between the two countries over the fate of thousands of Pakistani immigrants in Greece.

The Pakistani authorities took in 19 out of the 49 "illegal" immigrants on board the plane, all of whom had been deported from Greece.

They refused to take in the remaining 30, however, who could not prove their Pakistani nationality.

The plane, with the 30 remaining immigrants on board, was sent back to Athens following four hours of talks between Greek embassy officials and the Pakistani authorities at Islamabad airport. 

According to Interior Minister Chaudhry Nisar Ali Khan, the Greek government had deported the immigrants to Pakistan without providing sufficient proof of their nationality or the reasons for their deportation.

The Greek government, he said, had provided proof that only 19 of the immigrants bore Pakistani nationality.

The remaining 30, he added, had been sent back to Greece.

Last month, Islamabad announced that it would not allow any foreign planes carrying alleged Pakistani immigrants to land at its airports, stressing its refusal to take in any immigrants whose nationalities had not been proven before deportation. 

On Wednesday, Greek border guards used teargas to disperse hundreds of Pakistani immigrants who had converged on its border with Turkey.

There are no exact figures for the number of undocumented Pakistani migrants in Europe, but Interior Ministry officials put their number at many thousands.

Undocumented Pakistani and Afghan migrants usually enter Europe via the Greece-Turkey border after crossing Iran.

Each year, scores of them are killed by Iranian and Greek border guards.