India has stepped up security for the Pakistani High Commissioner to the country after he received an email threatening him, officials said on Monday, amid tensions between the two neighbours over the Mumbai attacks. A Pakistan High Commission official in New Delhi said the email, received about 10 days ago, threatened the envoy, Shahid Malik, would be killed if he did not immediately leave India. “We told Indian authorities and our High Commissioner's security has been increased,” Shah Zaman Khan, the high commission's press minister, told Reuters. “Whether it was prank or whatever, the matter had to be reported.” An Indian government official said security for Malik had been raised and, though the email seemed like a mischief, it was nevertheless being investigated. The lengthy email, written in English, was sent on behalf of a group calling itself the All-India Anti-Terrorism Group. It said Pakistan was linked to the Mumbai raids. “If the threat is taken lightly, it is 200 percent sure the envoy will be killed,” the letter said.