Saudi Arabia's King Abdullah has vowed to crush the "scourge" of al-Qaeda, in his first televised interview since becoming king.
The king is working to improve Saudi Arabia's image in the US
The king told US TV that Islam is a "religion of peace" that rejects the 11 September 2001 attacks, but admitted extremism had not been eliminated.
He also said he is working towards cutting oil prices after recent rises.
King Abdullah was crowned monarch of Saudi Arabia, the world's biggest oil exporter, in August.
The BBC's James Coomarasamy in Washington says his interview with ABC's Barbara Walters is part of a policy to improve his country's image in the US.
But, our correspondent says, he admitted that differences over Iraq, Afghanistan and the wider Middle East had soured Saudi public opinion about the US.
The king called al-Qaeda "madness and evil" and "the work of the devil" and vowed to fight "30 years if we have to until we eliminate this scourge".
"Such acts cannot be perpetrated by any individual who has a sense of decency or humanity or justice or faith," he said.
Admitting the extremist threat in Saudi Arabia remained, he questioned why the kingdom was the focus of world attention when it "exists in every country of the world".
King Abdullah insisted that his government had "withdrawn support for institutions that we found to be extremist".
The king told ABC that high oil prices had caused damage to other countries, but acknowledged his kingdom had benefited financially from them.
King Abdullah said Saudi oil production had soared to 10 million barrels a day to meet rising global demand and calm soaring prices.
"We believe that the damage to other countries is tremendous and we don't believe prices should be at this level," the king said.
On the subject of Iraq and reports that Iran was supporting insurgents, he said he hoped Tehran "will not become an obstacle to peace and security in Iraq".
Regarding women, whose rights and freedoms in the kingdom are severely restricted, the king said Saudi women would one day be able to drive.
"Our people are just now beginning to open up to the world and I believe that with the passing of days in the future, everything is possible," he said.