"We've already been at the highest state of alert since Sept. 11," Steets said. "We receive daily briefings from federal intelligence agencies including the latest FBI warning."

The FBI said Thursday al Qaeda may be plotting "spectacular" attacks in the U.S., with national landmarks or aviation, oil and nuclear industries as possible targets.

The FBI also said the Muslim extremist network may try to hit targets in the U.S. that would inflict massive casualties, psychological trauma and severe economic damage.

Steets said that Indian Point was already well protected by National Guard troops, marine patrols on the Hudson River next to the plant, and armed patrols in a secure area surrounding the power generation station.

However, the environmental group Riverkeeper said Friday that the FBI warning provided more fuel for its argument that the best way to boost security at Indian Point is to shut the plant down.

"In the case of Indian Point you have a nuclear plant that is located in the most densely populated part of the United States including New York City - there is no target that would cause more psychological damage if successfully attacked," said Alex Matthiessen, executive director of Riverkeeper.

Local communities and environment groups for decades have called for the shut down of Indian Point for health reasons. Since Sept. 11, opposition to the plant has been bolstered by concerns the station could be a target.

Matthiessen said Indian Point was not designed to defend a a massive, well coordinated attack and remains unprepared.

However, Entergy says Indian Point is vital to New York's energy supply and that shutting the plant would pose an economic disaster.

Steets estimated it would cost New York State an additional $1 billion per year to replace the cheap electricity generated at Indian Point, which supplies about 10 percent of New York City's power needs.