Washington, Dec 1 : US intelligence officials are searching urgently for clues that might identify the attackers and to ease tensions between India and Pakistan, even as Indian officials claim "elements in Pakistan" were involved.
FBI agents are in India to investigate the attacks in Mumbai that killed at least 195 people, including six Americans. US State Department has warned citizens still in India's financial capital that their lives remain at risk, CBS News reported.
A US counter-terrorism official said some "signatures of the attack" were consistent with the work of Pakistani militant groups Lashkar-e-Taiba and Jaish-e-Mohammed and reported to be linked to al Qaeda.
But the official emphasised it was premature to pinpoint who was responsible for the attacks.
Another official, specialising in counterintelligence, also cautioned against rushing to judgment on the origins of the gunmen who waged a two-and-a-half-day rampage through India's leading commercial center before being killed.
The US officials spoke on condition of anonymity due to the sensitivity of the situation.
US officials are concerned about a flare-up in animosity similar to one that occurred after Pakistani militants attacked the Indian parliament in December 2001, the officials said.
Underscoring those fears, Secretary of State Condoleezza Rice has called the Foreign Minister of India twice, along with Pakistani President Asif Ali Zardari, since the crisis began.
"There were very worrying tensions in the region. She was calling the president of Pakistan to get his read on how those tensions might be affected," said Gordon Duguid, a State Department spokesman.
President George W. Bush pledged cooperation with Indian authorities and mourned the deaths of at least 195 people at the hands of gunmen.
Bush was receiving regular updates, White House press secretary Dana Perino said Friday night. Senior administration officials were focused on ensuring that Americans were being helped in every way possible, she said.