Washington, Sep 10 (IANS): US Secretary of State Hillary Clinton said Friday that Al Qaeda was behind a new but unconfirmed terrorist threat against the US.

She was referring to the warning issued by the Department of Homeland Security Thursday night about "a specific, credible, but unconfirmed" terror plot to target New York and Washington, Xinhua reported.

Speaking at John Jay College of Criminal Justice in New York ahead of a key 9/11 anniversary, Clinton said a latest report showed that Al Qaeda is attempting to attack the US, in particular, to target New York and Washington.

She said that while the terror threat was still unconfirmed, the intelligence pointed to Al Qaeda elements who are behind the plot.

"We are taking this threat seriously," Clinton said.

She said the killing of Osama bin Laden "put Al Qaeda on the path to defeat, " and the raid on his compound was a "great tribute to the thousands of Americans and other people throughout the world who worked with us."

Facing the challenges of terrorism, Clinton said that state officials are combining diplomacy, development and necessary military actions to achieve short-term and long-term goals.

"We are waging a broad, sustained and relentless campaign that harnesses every element of American power against terrorism, and even as we remain tightly focused on the terrorist network that attacked us 10 years ago, we're also thinking about the next 10 years and beyond,"said Clinton

She suggested the New Yorkers to remain vigilant but not to let the latest terror threat affect their day-to-day lives.

A variety of commemorative events will be held this Sunday in New York City, the Pentagon in Northern Virginia and Shanksville, Pennsylvania, where terrorists hijacked passenger planes and crashed them Sep 11, 2001, killing nearly 3,000 people.