US Vice President Joe Biden (center) delivers a speech flanked by CIA Director Leon Panetta (right) and US Director of National Intellingence Dennis Blair (left).

WASHINGTON: Al-Qaeda is poised to attempt an attack on the United States within three to six months, America’s top intelligence officials have warned Congress.

The intelligence chiefs also warned that militant groups in Pakistan were coordinating their attacks with Al Qaeda, which had led to an increase in terrorist attacks inside Pakistan as well as rising concerns the groups might expand their ambitions to attack outside Pakistan.

Director of US National Intelligence Dennis C. Blair told the Senate Intelligence Committee that Al Qaeda and its affiliates had made it a high priority to attempt a large-scale attack on American soil.

Mr Blair said that Al Qaeda would remain intent on attacking in the US at least until Osama bin Laden and his second in command, Ayman al Zawahiri, were killed or captured.

Mr Blair, flanked by the directors of the CIA and FBI and the chief intelligence officers of the State and Defence departments, put Al Qaeda at the top of a threat list that included the Iranian and North Korean nuclear programmes, criminal cartels and the potential for economic collapse in developing countries hard-hit by recession.

CIA Director Leon Panetta told the congressional panel that the terrorist organisation was deploying operatives to the US, including so-called clean recruits with minimal terrorist ties and training, to carry out attacks.

Mr Panetta said Al Qaeda was also working to inspire home-grown extremists to trigger violence on their own.

The annual terror assessment highlights the growing concern that Al Qaeda is increasingly relying on these harder-to-detect militants who can use simple devices to carry out hastily planned attacks.

The intelligence officials and FBI Director Robert S. Mueller said US counter-terrorism agencies had absorbed the lessons of the Dec 25 attempted bombing of Northwest Airlines Flight 253 over Detroit, but all said future attempts were inevitable and could happen soon.

At Tuesday’s hearing, Senator Dianne Feinstein, the chairwoman of the Senate Intelligence Committee, asked Mr Blair to assess the possibility of an attempted attack in the United States in the next three to six months.

“The priority is certain, I would say,” he replied. Each of the four other officials, asked the same question, agreed with Mr Blair.

US intelligence chiefs also warned that Al Qaeda’s many affiliates were a great concern to the spy agencies. The Yemeni affiliate, which is believed to have directed the attempted Christmas Day attack on an American airliner, would continue to attempt additional attacks on the US, they said.The assessment was much starker than Mr Blair’s views last year, when he claimed a considerable progress in the campaign to debilitate Al Qaeda.