Islamabad has sent back 30 migrants that Athens was trying to repatriate. Interior Minister Nisar Ali Khan said Greece had failed to provide adequate proof that they were Pakistani citizens.
Shortly after the arrival of a chartered flight at Benazir Bhutto International Airport on Thursday, Pakistani officials refused to allow 30 of the aircraft's 49 passengers to disembark.
Pakistan's Interior Ministry said their identities had not been confirmed and therefore they could not be repatriated under a 2010 agreement with the EU to accept the repatriation of illegal Pakistani migrants.
"Any deportee with the unverified documents will be sent back on the same flight to the country he would arrive [from]," Khan said.
Misuse of EU-Pakistan agreement
Islamabad suspended its agreement with the EU last month, saying that some countries were abusing the law and deporting people of other nationalities to Pakistan.
The deal was reinstated last week, however, after EU Commissioner for Migration Dimitris Avramopoulos visited Pakistan to discuss the repatriation of migrants.
As the sixth most populous country in the world, Pakistan is one of the top five countries of origin for illegal migration to Europe. Thousands of Pakistanis travel to Europe illegally every year.
In a bid to control the number of migrants, Pakistan launched a nationwide crackdown against human trafficking last month. This resulted in the arrest of at least seven people alleged to be involved in trafficking.
ksb/jm (AFP, dpa)