South Korea struggled Thursday to determine the number of its tsunami victims in South Asia.

As of Thursday afternoon, South Korean Foreign Ministry confirmed six South Koreans were killed, 10 missing. But family members reported 654 cases of visitors to South Asia out of contact.

"It (verifying unaccounted-for claims) may take some time," South Korean Foreign Minister Ban Ki-moon was quoted as saying by Yonhap News Agency on Thursday.

Ban also said Vice Foreign Minister Choi Young-jin will fly to Thailand's southern resort island of Phuket later in the day to head the South Korean anti-disaster office there.

Moreover, South Korean government decided to commit an additional 3 million US dollars in emergency relief funds for the tsunami-hit countries. Previously, it had promised 2 million dollars donation.

Besides, South Korea will send a military cargo plane to Sri Lanka on Friday, carrying medical supplies and relief workers, Bansaid.

But the ministry officially denied a western news agency's Wednesday report that 36 South Korean were killed in Thailand, Yonhap said.

Officials said they were trying to check immigration records in cooperation with Thailand and other tsunami-affected countries where the travelers headed, but added they were experiencing difficulties, mainly from a lack of information from relatives.