File Photo: US President Barack Obama. (AP Photo)

Ahead of President Barack Obama's visit to India, the US has asked Pakistan to ensure that there is no cross-border terror incident during the trip and subtly warned of "consequences" if any such attack is traced back to the country, sources said.The warning has been issued keeping the track record of Pakistan-based militant groups that have carried out attacks in India that have coincided with high-profile visits from the US.Militants had shot dead 36 Sikhs in March 20, 2000, in the Anantnag district of Jammu and Kashmir, coinciding with the visit of the then US President Bill Clinton to India.Mr Obama will travel to New Delhi later this week to attend the Republic Day parade on January 26.Ahead of the presidential trip, there is an unprecedented level of intelligence sharing between India and the US.At least 10,000 paramilitary troops will be deployed along with the 80,000-strong Delhi Police to ensure fool-proof security in and around Rajpath -- the main venue.A seven-layer security ring will be thrown around the Very Very Important People or VVIP enclosure at the venue and the airspace over the area would be monitored by a radar to be specially set up.This will form part of the planned unprecedented ground-to-air security drill that will turn the national capital into an impregnable fortress during Obama's visit.

The US forces in Afghanistan are also keeping a close eye on the activities of the terrorist groups in the region.