Al-Qaeda [Images] chief Osama bin Laden on Thursday warned of new attacks being planned on the United States.

In a recording aired on al Jazeera television channel, Osama said, "We have seen explosions in many European countries. As for similar operations taking place in America, it's only a question of time. They are under way, and you will hear about them soon."

The dreaded terrorist, however, also offered a 'long-term truce' to the Americans.

A senior unnamed United States counter-terrorism official has been quoted in the media as saying that the audio airing of Al Jazeera was being examined.

Intelligence agencies are trying to determine a number of things including authenticating the voice of the al Qaeda leader as also finding out when the tape was made.

"The operations are under preparation and you will see them in your houses as soon as they are complete, God willing," said the speaker on the tape, who sounded like bin Laden.

The last time Osama released a tape was back in December 2004.

Intelligence agencies and senior officials of the US administration had been wondering the long silence of bin Laden.

The impression has been that both bin Laden and his Number Two Ayman al Zawahiri are holed up in the mountainous region between Pakistan and Afghanistan.

On January 13, an unmaned drone supposedly operated by the Central Intelligence Agency unleashed four Hellfire missiles in the tribal village of Damadola inside Pakistan killing at least 18 people, including women and children.

With PTI inputs