Oliver North admitted Friday he lied to House members in 1986 about his activities for Nicaraguan rebels and did not pay for a security system installed at his home but said he did not believe he acted illegally.

Directly addressing some of the 12 felony charges against him, the former staff member of the National Security Council described himself as a lowly Marine Corps officer carrying out standing orders from White House superiors.North said he lied to the lawmakers when they questioned him about his clandestine activities for the Contra rebels but said he did so because his superiors told him to keep the project secret.

"I was put in a situation, having been raised to know what the Ten Commandments are, I knew it would be wrong to do that but I didn't know it would be unlawful. "I felt like a pawn in a chess game being played by giants," he said of being caught in a "bitter political dispute" between Congress and the White House over support for the Contras.

North's second day of testimony closed the seventh week of his criminal trial on charges including lying to Congress and destroying official documents. If convicted he faces 60 years in prison and $3 million in fines.

The retired Marine lieutenant colonel has claimed his White House superiors - including former President Reagan and President Bush, vice president at the time - knew of and authorized his activities to support the Contras with a private network and to arrange for the secret U.S. arms sales to Iran.

In fact, North testified Friday, the arms sales were so secret that when they were revealed in early November 1986, "the president himself had categorically denied some of the things we had been doing" to buy the freedom of American hostages held by pro-Iranian extremists in Lebanon.

Reagan did deny initial reports that the United States sold arms to Iran but later said the deals were made to reach out to "moderate" elements in the government of Ayatollah Ruhollah Khomeini and were not arms-for-hostages trades.

North's defense team also has attempted to paint nearly the entire Reagan Cabinet as being deeply involved in secret efforts to arm, finance and support the Contra rebels at a time when Congress had banned official U.S. aid. The defense also wants to portray their client as the only person to come to trial in the scandal.

Bush once noted North's work approvingly in a Nov. 27, 1985, card North read to the jury: "Dear Ollie: As I head off for Maine for Thanksgiving, I want to wish you a happy one. . . . One of the things I am thankful for is the way you have performed in a tough situation under fire" in handling "the hostage thing and Central America."

"Get some turkey," the note ended.

Another felony charge against North accuses him of accepting an illegal gratuity of a $13,800 home security system in 1986. North testified he took the system because Abu Nidal, "the world's most notorious terrorist," threatened him, and he feared for his wife and four children.

Defense lawyer Brendan Sullivan played a videotape of a CBS News broadcast from late April 1986 reporting the death threat and asked, "How did you react to that?"

"I don't want to sound like I'm macho because I don't think I am," said North, staring at his hands and twirling his Naval Academy ring. "But I was very disturbed that my wife and children could be the victims of something like that because of my work."