More than 5,000 terrorists have been captured or killed in the 5 years since 9/11 terror attacks, CIA Director Michael Hayden said Monday.

"Al Qaida's core operational leadership has been decimated, and their successors are in hiding or on the run," Hayden said when he addressed CIA employees at the fifth anniversary of the catastrophic attacks which claimed nearly 3,000 lives.

While acknowledging 9/11 attacks have dealt an "unforgettable blow" to his agency, he said CIA's cooperation with foreign intelligence agencies has led to many successes in breaking up terrorists' cells and dismantling of al Qaida.

In such a way many large-scale terror plots have been foiled, although some schemes have succeeded beyond U.S. territories, said Hayden.

Shortly before his remarks, al Qaida's number two Zayman Al- Zawahiri released a video tape threatening new attacks.

Source: Xinhua