Pakistan's Foreign Ministry spokesman Nafees Zakaria briefs media at the Foreign Office in Islamabad, Pakistan, Thursday, May 18, 2017.
The staffers were identified as Hassan Khanzada, visa assistant at the embassy, and Syed Munir Shah, staff driver, the "Dawn" reported.
The staffers were held for hours by NDS and the incident serves another blow to the already cold relations between the two countries.
Kabul police said they were not aware of any detentions.
The Afghan foreign ministry, reportedly after a bit of dilly-dallying, conceded that the two men had been taken into custody by the NDS, the report said. Khanzada and Shah were finally released after three hours, it said, adding that it was unclear why the staffers were detained.
Afghanistan's intelligence agency, the National Directorate of Security, had detailed two staffers at the Pakistan Embassy in Kabul, prompting Islamabad to lash out at its neighbour for what it called was a violation of the Vienna Convention of Diplomatic Relations.
"It was emphasised that such incidents undermined the constructive engagement which the two countries envisaged for strengthening of bilateral ties", the statement said.
In an incident which shows Pakistan's hypocrisy on worldwide ties, it was forced to cite that one of the provisions of Vienna Convention was violated when Afghanistan today picked up two Pakistani embassy staffers in Kabul.
Pakistan lodged a strong protest with Afghanistan after two of its diplomats posted in Kabul were reportedly detained by Afghan security agencies on Wednesday - in a latest incident suggesting simmering tensions between the two neighbours.