India has sought the extradition of Khalistani terrorist Paramjit Singh Pamma from Portugal where he was arrested because his crimes were committed in India, the government said on Thursday.

"As far as we are concerned, it is very clear that Paramjit is a known terrorist and has Interpol red corner notice against him," external affairs ministry spokesman Vikas Swarup said in response to a question at a media briefing here.

Pamma, who has been staying in Britain on political asylum since 1994-95, was reportedly arrested along with his family from a hotel in Portugal on December 18, 2015 based on an Interpol red corner notice issued against him.

"Paramjit Singh is accused of a number of criminal cases in India, including the murder of the president of the Rashtriya Sikh Sangat. And for this reason we are seeking his extradition from the government of Portugal," Swarup said.

India has accused Pamma of hatching a plot in Britain to kill Rulda Singh, chief of the Rashtriya Sikh Sangat, an affiliate of the RSS, in 2009.

According to a statement issued by the New York-based Sikhs for Justice advocacy group, Pamma's Britain-based lawyer has claimed that India's extradition attempt was a case of "double jeopardy" as the British authorities have already carried out an investigation at India's insistence and found no credible evidence against his client.

According to Indian authorities, seeking Pamma's extradition was right.

"We want to try him in India because the crimes he is accused of occurred in India," Swarup said.