UN Secretary-General Ban Ki-moon on Sunday sent a letter to South Korean President Lee Myung-bak extending sympathy and solidarity to the people of South Korea, Xinhua reported.
In the letter, the secretary-general said that it was "with shock and sadness" that he learned of the incident involving a South Korean naval ship off the west coast of the Korean Peninsula, said a note emailed to the press from the office of Ban's spokesperson.
"I hope that the on-going search and rescue mission will be conducted swiftly," the secretary-general said. "I would like to extend my deepest sympathy and solidarity to the Korean people through you."
On Saturday, the UN chief expressed his condolences to the families of the victims and the government and people of South Korea, according to the office of Ban's spokesperson.
The South Korean military on Sunday stepped up its efforts to rescue 46 missing sailors from the warship that sank early Saturday, but the operation has not made any progress.
According to the state-run broadcaster KBS, a 86-member naval rescue team has launched underwater operations earlier in the day, trying to determine the exact location of the sunken ship and confirm whether there are survivors.
After repeated failures due to rough waves and low temperature, the military divers finally located the front of the ship, which is believed to have been split into two by an unexplained explosion.
There were a total of 104 crew members onboard when the ship sank. Only 58 of them have been rescued and the other 46 remain missing. Enditem