Investigations into the origins of the Mumbai terror attacks [Images] are still on and the Federal Bureau of Investigation continues to assist Indian agencies, authorities in the US have said, following reports that the Pakistani probe indicates that the strike was planned outside the country.

"I believe the investigation is ongoing as to the origins of the attacks," a National Security Council spokesman said when asked about news reports in this regard coming from Pakistan.

"We urge continued cooperation and close communication between India and Pakistan to bring the perpetrators to justice," the spokesman said.

The FBI declined to comment on specific questions related to the Pakistani probe into the attack and referred the query to Islamabad [Images].

FBI spokesperson Richard Kolko said that the agency continues to assist Indian authorities with their investigations into the Mumbai attack.

At least 180 people, including six US nationals, were killed when ten terrorists opened fired on people at various places in Mumbai on November 26.

India has blamed the attack on terrorists based in Pakistan and has demanded action against those responsible.

The FBI spokesman said the cooperation between the law enforcement agencies in India and the FBI has gone very well.

"The agencies (FBI and its Indian counterpart) have shared information and expertise and we will continue to do so," Kolko said.

"Our agents in the US and at our legal attaches assigned to many embassies continue to investigate many leads," Kolko said.