Opposition leader Kim Dae Jung said today he had suffered mentally "beyond description" during lengthy prison cell interrogations by military authorities who wanted him to confess that he had plotted to overthrow the government.

Kim told a military tribunal he was questioned 15 hours a day for two months and was sometimes stripped naked and "driven to the very point short of torture."

Giving details of his internment for the first time, Kim said this morning that he had signed some statements "against my will" because he became exhausted mentally and physically.

Kim's dramatic account was given in a brief courtroom statement on the second day of testimony in his sedition trial, which could end in a death sentence for the 56-year-old political veteran, who in 1971 was almost elected president.

Military authorities denied earlier that Kim was tortured, but have said nothing about his interrogation in a military detention center where he was taken after being picked up in a sweeping series of military arrests last May 17.

A statement by families of Kim and 23 other defendants had alleged some were tortured into making false confessions that they had defied the law.

Military authorities sought to keep Kim's account from the public today by censoring his remarks from a pool report written by one of two foreign reporters present in the courtroom. But diplomatic sources also present in the room later confirmed Kim's remarks.

The censorship of similar material yesterday was protested by several foreign reporters. Asked today for an explanation of the censorship rules, a spokesman for the martial-law command said it was being employed because of what he termed "wrong" reporting by foreign journalists of the violently suppressed civil insurrection in the city of Kwangju in May.

The spokesman explained his command had been unable to "control" the reporting of that affair but was determined to act differently in the case of Kim's trial.

Kim also denied today that he had ever plotted a violent overthrow of the government, a charge which is the core of the government's allegations against him. A prosecutor charged Kim had intended to create campus unrest and cause riots last spring that could have toppled the government of the then president Choi Kyn Hah.

"It is not true," Kim replied. "I thought the situation could be dealt with only by public opinion, not by violence."

Kim said he was kept in an underground room for 60 days and underwent questioning everyday from 9 a.m. until midnight.

He said that he told the investigators he had never planned a violent seizure of power. But they refused to believe him, he added.

The told him it would be better to admit his crimes, because he would have an opportunity to deny them in court later, Kim testified.

Kim said he had a weak heart, and the interrogation became "too much for me to stand." He was "extremely tired" mentally and physically and therefore signed some statements against his will, planning to deny them later in court, he said.

Unlike yesterday, when he refused to answer prosecutors' questions, Kim today spoke out in crisp, clear statements, responding to interrogation about his activities abroad when he was in self-imposed exile in the early 1970s.

Kim left the contry after losing narrowly to the late president Park Chung Hee in the 1971 election.

Part of his exile was used to mount a public opinion campaign against the Park regime in both the United States and Japan. One of the prosecution's claims is that he was involved at the time with Communists sympathetic to the government of North Korea.

Other questions dealt with his activities after Park's assassination last October, when Kim was attempting to build a power base to run for president this year or next. Kim undertook a wide-ranging campaign, on and off college campuses, and slowly built an organization to support himself across the country.

The prosecution is trying to assert that these activities led to the wave of student protests in early May and ultimately to the citizens' rebellion that swept Kwangju after Kim and many others were arrested on May 17. More than 260 persons were believed killed in the Kwangju uprising.

Kim conceded under questioning that he had received money from foreigners in the early 1970s, including some from an American identified only as "Ed Baker" and had used it to finance his political efforts in South Korea. Some money was paid to Korean politicians supporting him, he testified.