Addressing a packed forum, Abizaid, who spoke without a script and sat throughout his talk, said the rise of Islamic extremism and the Arab-Israeli conflict were the major obstacles facing the region.

"I believe our failure to address these problems of extremism will lead to World War Three," Abizaid said.

Outside, around 35 protesters chanted, "While Abizaid is lying, Iraqi people are dying" and "While Abizaid is lying, American troops are dying."

But Abizaid defended the presence of American troops in Iraq.

"We don’t come as an oppressor. We don’t come as an occupier. We’re not gaining any money by being there."

And in keeping with his recent testimony before Congress, Abizaid also would not give a timetable for withdrawing from Iraq.

"I understand that American troops are not popular in the middle of downtown Baghdad," he said. "We don’t want to extend our stay. But we have to stabilize the region."

Abizaid also said that resolving the Arab-Israeli conflict was key to resolving the strife in the Middle East.

"The Arab-Israeli conflict over time works against the peace and tranquility of the region," he said. "We’ve got to move the peace process forward in the Middle East."

Abizaid said that extremists in the region fell into Sunni and Shi’ite extremist camps.

He compared the rise of the Sunni extremist camp—in the form of Al-Qaeda and afilliated-groups—to the rise of Fascism in Europe during the 1920s.

"Bin Laden is among the deadliest enemies that America has faced since Nazi Germany," he said. "We have to defeat the extremism of Bin Laden. It’s bloody. It’s merciless."

But while Abizaid advocated direct action against Al-Qaeda, he stressed that he did not advocate that approach for Shi’ite extremists—whom he identified with the Islamic regime in Iran.

"As far as [Shi’ite] extremism is concerned, we’ve got to contain Iran," Abizaid said. "And I said contain it. I didn’t say invade it."

"Over time, the rich cultural heritage of Iranian civilization will triumph over this dark ideology that they have adopted for the short term," he said.

Abizaid said that there were elements of the Arab-Israeli conflict and the rise of Sunni and Shi’ite extremism in the Iraqi conflict.

"Where these three problems come together happens to come in a place called Iraq," he said.

At several points, Abizaid cracked jokes.

"It’s a complicated problem. I look forward to the day I retire," he said near the end of the talk, eliciting laughter.