Pakistan top security adviser has been sacked after apparently confirming Indian claims that the lone surviving suspected gunman from November's deadly Mumbai attacks is a Pakistani national.

A short statement issued by the prime minister's office late on Wednesday said Mehmud Ali Durrani, the National Security Adviser,  was removed "for his irresponsible behaviour for not taking [the] prime minister and other stakeholders into confidence, and lack of co-ordination on matters of national security."

Durrani was quoted by several television news channels, including the India-based CNN-IBN, as saying that Ajmal Amir Qasab, the only suspected arrested in the Mumbai mayhem, was a Pakistani national.

The surprising dismissal came hours after the state-run Associated Press of Pakistan newswire cited a foreign ministry spokesman as confirming that Qasab "is a Pakistani national and further investigations are being carried out".

India has long been insisting that the arrested suspect was a Pakistani, and on Tuesday officially gave Islamabad the information that New Delhi says links the perpetrators to elements inside Pakistan.

Relations between New Delhi and Islamabad are at the lowest ebb since the November 26 attacks in India's financial hub of Mumbai, where more than 170 people were killed by 10 armed men believed to be linked with the Pakistan-based Lashkar-e-Taiba organisation.