Two North Korean youths, both students at a dental college in Prague, Czechoslovakia, arrived in Seoul Saturday after defecting through a western European country.

Cho Sung-kun, 22, son of a North Korean colonel, and Kim Un-chol, 23, son of a blue-collar worker, landed at Kimpo Airport Saturday evening on a Korean Air flight from London, and met with reporters at the airport."I have a good family background according to North Korean criteria," Cho said. "My father is a senior colonel and I was one of those trusted by North Korean government people. It is not easy for ordinary youths to come out for study overseas."

Cho said he was respected in North Korean society but after one year in Czechoslovakia, "I began thinking that I should defect no matter what - whether my study was completed or not."

"In North Korea there are no freedoms at all, not the least one," Cho said. "If you are born in North Korea and live all your life there you will never know. Once you are abroad, then you know things in North Korea are not right."

"I simply did not want to go back."

The two defectors said they arrived in Czechoslovakia on Sept. 3, 1986, with about 40 other North Korean students. Cho said about 150 North Korean students study in Czechoslovakia.

Cho said he began thinking of defection about a year ago, while Kim said he decided last November. They said they agreed in December to defect together.

It was the second North Korean defection case in nine months. Last May, Kim Jung-min, a North Korean official handling foreign trade, defected through an eastern European country and came to Seoul.

Earlier, Foreign Ministry spokesman Chang Hoon said the two dental students came to a South Korean embassy in a western European country seeking asylum.