This story was originally published March 25 at 12:10 p.m. It has been updated.

A crack through the Navy's Arctic ice camp forced submariners and researchers to break camp in a hurry Thursday.

More than 40 international researchers and personnel were evacuated by aircraft back to the U.S. after the crack was discovered, bringing the Navy's biennial ice station to a premature close, according to two officials familiar with the exercise. The operation, which began in early March, was slated to run another week.

The camp was being packed up early prior because another crack farther away had been discovered earlier in the week. The evacuation kicked into high gear when the second crack ripped through the camp.

While the people were evacuated, some of the equipment was left and would have to be retrieved later, one official said.

Ice Camp Sargo consists of shelters, a command center and infrastructure to house and feed more than 70 people at a time.

The evacuation of Sargo was reminiscent of the evacuation of Ice Camp Nautilus in 2014, almost two years ago to the day. The camp is set up every two years to assist two attack submarines conducting operations under the ice floes in the Beaufort Sea. It also serves as a base camp for researchers testing ice thickness, among other things.

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While the researchers were disappointed to leave a week early, the Navy still counts the mission a big success, said Cmdr. Tommy Crosby, spokesman for Submarine Force Atlantic.

"The vast majority of the experiments being conducted were completed, all but two" Crosby said, adding that while the camp was demobilized, the Navy was pressing on with its submarine-based experiments.

The attack submarines Hampton and Hartford are stalking around under the ice floes as scheduled, Crosby said.

"The exercise is still ongoing," Crosby said. "Hampton and Hartford are resuming their regularly scheduled operations."