India has ordered its border forces to "a high state of vigil" after the assassination of Benazir Bhutto raised the spectre of chaos in Pakistan spilling over to its nuclear-armed neighbour.
Relations between India and Pakistan, who have been to war three times and nearly came into conflict as late as 2002, are always fraught with tension despite a fragile peace process in the last few years.
"There has been a general advisory to all the border forces to maintain a high state of vigil. You can guess why," a Home Ministry spokesman told Reuters on Friday.
"There are no specific threats as yet. They have been put on alert, there have been various speculations, jihadis, the spillover effect."
India often orders its forces on alert in response to crises in Pakistan, which also has nuclear arms, and did so in November when President Pervez Musharraf declared a state of emergency.
Washington and many Western allies view Pakistan as a bulwark in the U.S.'s "War on Terror" after the Sept. 11, 2001 attacks on the United States. Pakistan is seen as key to a victory of Western allies against Taliban insurgents in Afghanistan.
But for India, the worry is that instability in Pakistan may spill over the border and lead to increased militant attacks in Indian-ruled Kashmir or bombings of Indian cities.