The threat is far from gone.

The potential for another devastating terrorist attack “remains very real,” Defense Secretary Leon Panetta said yesterday after a somber visit to Ground Zero.

The Pentagon chief’s startling remarks came after he walked through the National September 11 Memorial park and museum with Mayor Bloomberg.

“The potential for that kind of attack remains very real,” Panetta said from the 10th floor of 7 World Trade Center.

Noting that many of al Qaeda’s top leaders, including Osama bin Laden, have been captured or killed in recent months, Panetta said the nature of the terrorist threat has evolved to the point where al Qaeda “nodes” outside of Afghanistan and Pakistan are now the most dangerous.

“Yemen has risen to the top of the list,” he said.

Panetta’s New York visit gave him an early glimpse at the memorial, with its majestic 30-foot-tall walls of water.