Senior Indian officals have warned have warned that Sikh militant groups in the UK may be planning and funding attacks on targets in India.
On 4 March, the BBC's File on Four programme quoted senior Indian police offiers as saying that money raised by Sikh groups in the UK is being used to "fund militant activities in the Punjab".
NPS Aulakh, the chief of the Punjab Police, told that BBC that money was reaching militants from British-based supporters via informal funding channels in the Sikh community.
"We have had some intelligence and from interrogations that some of the people in Britain were involved in funding activities of terror," he said.
On Thursday, India's prime minister, Manmohan Singh, who is himself a Sikh, warned that Sikh militant groups in Canada, Germany and the UK were regrouping and could be planning to resume violent effort to establish a separate Sikh state.
"The government and our agencies have credible information of efforts being made by extremist groups to revive militancy in Punjab," he said in a letter to head of Sikh temples in India.
Other senior Indian officals have warned that Pakistan has sought to support Sikh separatist groups. Last year, MK Narayan, India's National Security Adviser, year warned that there had been "a manifest attempt in Pakistan to build up a radical Sikh environment".