SEOUL/NIIGATA (Yonhap) -- The South Korean government has pulled all members of its rescue team sent to quake-stricken Japan out of the ravaged city of Sendai due to concerns about the workers' possible exposure to radiation, a senior government official said Saturday.

   "Some members of the team who had remained in Sendai are moving to Niigata, where the main force is staying," said the official.

"They will join the main force later in the day."

   Seoul moved about two-thirds of its 107-member team of rescue workers from Sendai on the east coast to the western coastal city of Niigata on Friday, as there is a risk of harmful radioactive contamination in the eastern coastal region.

   Thirty-one members will arrive in Niigata around 3 p.m., added the official.

   A foreign ministry official noted that the retreat is not solely based on the explicit threat of radiation leakage from nuclear power plants in Fukushima, about 250 kilometers northeast of Tokyo.

   "We moved the rescue team to Niigata as our rescue mission in Sendai has been completed," said an official from the foreign ministry in Seoul. "They will be stationed in Niigata and schedule further rescue missions with the Japanese government."

   As fears of a potential nuclear disaster at the power plant have deepened, the South Korean government also urged its nationals in Japan to move as far away from the Fukushima No. 1 plant as possible.

   Radiation levels around the facility have increased significantly after a series of explosions hit the plant in the wake of a massive earthquake on March 11.