(CNN) -- U.S. Coast Guard and military aircraft Saturday are en route to the western Pacific, where a nuclear attack submarine ran aground, wounding several crew members -- including at least one critically -- according to the U.S. Pacific Fleet.
The USS San Francisco ran aground some 350 miles south of Guam -- the nearest land mass -- while it was conducting submerged operations. It has since resurfaced and is heading back to Guam, according to the USPF's news release.
"At this point there does not seem to be damage to the (nuclear) reactor," Lt. j.g. Adam Clampitt told CNN, from his base in Pearl Harbor, Hawaii.
The accident happened Saturday at noon, Guam time (Friday 9 p.m. ET, 4 p.m. Hawaii time).
The nuclear-powered vessel is a Los Angeles-class "fast attack" submarine. Clampitt says it was carrying four torpedo-tubes, which can launch Tomahawk cruise missiles. It is the most common type of U.S. attack submarine in the naval fleet since 2004.
Clampitt said there are 137 crew members on board the USS San Francisco.
The nuclear submarine has a "limited medical staff on board," he said. Most of the wounded suffered head injuries, Clampitt said.
"Our first concern is the safety of the crew," Clampitt said.
The aircraft are bringing medical staff and investigators to assess the extent of the injuries and damage to the submarine.
They were in high speed transit submerged. Thats the worst type of grounding incident you can have on a submarine, and it can be potentially fatal to the entire crew. Right now, those guys are in a fight to get the ship into port, because there is most likely damage to the ballast tanks, and they are fighting to keep it afloat
The nuclear submarine has a "limited medical staff on board," he said. Most of the wounded suffered head injuries, Clampitt said
I servd on the sister boat of the San Fransisco. There is one senior corpsman on a 688 class boat, and whoever is qualified as an EMT or whatever in civilian life. This guy is probably workig himself half to death right now
Head injuries infer a high speed collision, resulting in the crew really being tossed around. There are plenty of things on a submarine that your head can hit, and they dont move at all. I still have scars
Pray for these guys folks...they have a long way to get to port..at least another day, or even more if they can't do any speed at all.
Theres an understatement