At the University of Texas, a message posted on the university's Web site said: "Evacuation due to threats on campus.
Chief Schmitt said evacuation sirens and announcements in Sitka came shortly after the quake, prompting the temporary rush by residents to higher ground.
The previous year, the N.R.C. said it would license the Shoreham nuclear plant, on Long Island, even though New York State said evacuation was not possible.
It said evacuation plans for the area surrounding the plant were unworkable, especially in the event of a large release of radiation from a terrorist attack.
Jim Steets, a spokesman for Indian Point, said evacuation and emergency preparedness planning was being constantly refined and that the nuclear industry expected to adapt and to learn lessons from the disaster in Japan.
Civilians and the wounded in the eastern part of the city were expected to begin leaving the city at 6am but four hours later sources on the ground said evacuation teams had not yet crossed into the opposition enclave and there were reports of gunfire.
