Two Chinese Christian missionaries operating in Pakistan have been abducted and killed by ISIS. The pair were preachers who had pretended to be business people in order to enter the country.

Lee Zing Yang, 24, and Meng Li Si, 26, were identified on Monday by Pakistan's interior ministry, who said the pair's visa rule violations had played a role in their abductions.

The two preachers were abducted by armed men who had pretended to be policemen on May 24 in Quetta, the capital of Pakistan's Baluchistan province. Last week Islamic State's Amaq news agency reported that the men had been killed by ISIS.

'The minister observed that it is highly unfortunate that a misuse of the terms of (the) business visa contributed to the unfortunate incident of abduction and subsequent murder of two innocent Chinese,' the ministry said.

Earlier reports had suggested that the couple were teachers in a Chinese private school, but its now understood that they were using business visas as a front for their missionary work.

'Instead of engaging in any business activity, they went to Quetta and under the garb of learning (the) Urdu language from a Korean national...were actually engaged in preaching,' the ministry's statement said.

The incident has prompted calls for review of Pakistan's security and visa processes for Chinese nationals, and a databank that would track Chinese nationals working in Pakistan. China's foriegn ministry previously said it would cooperate with Pakistan in the investigation, and said it opposed all forms of terrorism.

Additional reporting by Reuters