SACRAMENTO, Jan. 5—Almost as soon as it began, the Unabomber trial came to a mysterious and sudden stop today when Theodore J. Kaczynski blurted out to the court that he had a "very important" statement to make about his relationship with his attorneys. He was immediately ushered into the judge's chambers with his attorneys for more than four hours of discussion. Opening statements, scheduled to begin this morning, were delayed until Thursday at the earliest. The jurors, who had not yet filed into the courtroom when Kaczynski staged his outburst, were excused until then.

While the exact nature of the conference was not revealed, leaving Kaczynski's first public utterance since his arrest largely wrapped in mystery, U.S. District Judge Garland Burrell Jr. -- and Kaczynski's own words -- indicated the defendant is again wrangling with his own attorneys.

"Your honor, before these proceedings begin, I would like to revisit the issue of my relationship with my attorneys," Kaczynski declared. "It's very important. I haven't stood because I'm under orders from the marshals not to stand up." Kaczynski has previously fought with his lawyers over their attempts to portray him as mentally ill. At least two mental health experts, hired by the defense, have examined Kaczynski and concluded the former University of California at Berkeley mathematics professor turned mountain man suffers from the delusions of a paranoid schizophrenic.

Kaczynski himself has resolutely denied that he is, as the recluse put it in one of his own journals, "a sickie." He has refused to be examined by government psychiatrists and has cut off interviews with his own doctors when they broached the subject of his possible mental illness.

Because of Kaczynski's refusal to be examined by government experts, his defense team has been denied the opportunity to offer mental health testimony during this phase of his trial. Efforts by his attorneys to secure a plea bargain -- an admittance of guilt in exchange for a life sentence rather than the possibility of death -- have been rebuffed by prosecutors.

A few minutes before the trial was to begin, Kaczynski, dressed in a bulky white knit sweater and blue pants, marched stiffly into the courtroom and immediately confronted one of the main advocates of the proposition that he is mentally incompetent to stand trial -- his younger brother David.

David Kaczynski sat in the front row, his arm wrapped around the shoulders of their mother, Wanda. The two held hands tightly as Theodore Kaczynski averted his eyes, turned his back to them and sat down, only a few feet away. Wanda Kaczynski wept quietly.

It is believed to be the first time the two brothers have been face-to-face since David Kaczynski alerted the FBI two years ago that his brother might be the elusive Unabomber, the anti-technology terrorist who officials say was responsible for 16 mail bombs, which killed three and injured another 29. In the current trial, Kaczynski is charged only with four bombings, which killed two and injured two.

In the courtroom today, Theodore and David Kaczynski looked like brothers no matter how estranged. Both were bearded, and they even shared the same cowlick. They are bonded by bloodline but have vastly different personalities. One is quiet and withdrawn and given to bouts of melancholy, the other outgoing and happy-go-lucky, according to friends in the Evergreen Park, Ill., neighborhood where they grew up.

At times, they shared what on the surface appeared to be a normal sibling relationship. They played friendly but competitive games of Monopoly and occasionally performed musical duets, with Ted on the trombone and his little brother on the trumpet. One of David's earliest memories was when Ted fashioned a special knob on the family's screen door that the younger boy could reach.

But those moments of normalcy soon came to be overshadowed by the dark side of the older brother, particularly in his outbursts of seemingly irrational antagonism toward their parents.

Over the years, Theodore wrote his parents increasingly hostile letters in which he accused them of ruining his life and being responsible for his inability to make friends or establish relationships with women. David recalled one letter his brother sent to their parents in which he wrote, "I can't wait until you die so I can spit on your corpse."

Although David Kaczynski's tip led the FBI to arrest his brother at his isolated shack in Montana, the younger Kaczynski has since damned the government for its insistence on seeking the death penalty. The younger Kaczynski has said his brother deserves help, not a lethal injection.

Some of his victims do not agree.

Seated in the front row, behind the prosecutors, were two men injured in the bombings -- Charles Epstein, a geneticist at the University of California at San Francisco, and Yale computer science professor David Gelernter. Gelernter, whose right hand was disfigured by an explosive mailed by the Unabomber, has called his alleged assailant an evil coward who deserves to die.

Neither Epstein nor Gelernter spoke with reporters today. They are expected to be called as witnesses in the trial.

But Mark O'Sullivan, an FBI chaplain who is serving as the spokesman for the family of slain forestry lobbyist Gilbert Murray, said the family was "extremely disappointed to have the defendant stand up and grind things to a halt today."

In court, federal prosecutor Robert J. Cleary also expressed frustration, asking Judge Burrell to "firmly and finally" resolve the disagreements between Kaczynski and his lawyers.

Burrell said he was trying but suggested it was not easy. "A criminal proceeding sometimes involves dynamics that a judge has to react to," he said.

If Kaczynski is trying to dismiss his court-appointed attorneys, it will be difficult at this stage, according to legal experts, but not impossible. One San Francisco defense attorney's office confirmed that it had been contacted by the judge today.

Other attorneys could be appointed, but that might delay the trial for weeks if not months and may require the two sides to go through lengthy jury selection all over again.

The case against Kaczynski is seen by observers as almost overwhelming. Found in his 10-by-12-foot Montana cabin was a trove of damning evidence, including coded journals that read like virtual signed confessions, as well as a signature explosive device in the Unabomber style and a draft of the Unabomber's 35,000-word manifesto raging against industrial society.

Staff writer William Claiborne in Los Angeles contributed to this report.