NEW YORK, JUNE 21 -- Nelson Mandela, aggressively defending his views in a television interview, described Palestine Liberation Organization leader Yasser Arafat today as "a comrade in arms" and said it would be "a grave mistake" to change his view of Arafat "on the basis of the interests of the Jewish community."

During an ABC News "town meeting" taped before 1,000 people at City College in Harlem and broadcast hours later, the South African black leader also repeated his support for Libyan leader Moammar Gadhafi and Cuban President Fidel Castro, saying they and Arafat "support our struggle to the hilt" and that he had no problem with their approach to human rights.

Mandela also was critical of South African President Frederik W. de Klerk, insisting that the Pretoria government has "deliberately" failed to suppress factional violence in black provinces and did not deserve even a gesture of support from the United States. "Mr. de Klerk has done nothing . . . . What are you rewarding him for?" Mandela asked.

Mandela's comments, on the second day of an eight-city U.S. tour that is to take him to Washington Sunday, seemed all the more controversial because the rest of his New York visit has been wrapped in a cocoon of celebratory rhetoric and cheering.

Tonight at Yankee Stadium, a mostly black crowd of more than 40,000 roared when Mandela donned a Yankees cap and warmup jacket and declared: "I am a Yankee!" The spectators, many of them wearing African garb or Mandela T-shirts and waving "Free South Africa" signs, had been dancing in the aisles to such artists as The Mighty Sparrow, a calypso singer, while Mandela's likeness beamed from the scoreboard.

The leader of the African National Congress thanked those in the Bronx ballpark, saying: "We have broken the walls of the South African jails . . . . Apartheid is tottering on the brink of its demise . . . . Victory is in sight."

The concert followed a Harlem rally who heard Mandela and his wife, Winnie. Earlier, Mandela was buoyed by a moving ecumenical service at Riverside Church, beaming and swaying during a spontaneous eruption of hand-clapping, dancing and Zulu chanting led by South African exiles.

For a man who languished in South African prisons for 27 years, Mandela, 71, proved a surprisingly agile debater under the glare of American television lights. After one particularly aggressive answer, as moderator Ted Koppel appeared speechless while waiting for his guest to finish, Mandela said: "I don't know if I've paralyzed you."

Mandela diplomatically ducked when a questioner from the audience asked why he did not denounce racism in the United States. He said it "would not be proper for me to delve into the controversial issues which are tearing the society of this country apart."

Mandela was less reticent when asked about his alliance with Arafat, Gadhafi and Castro. "Our attitude toward any country is determined by the attitude of that country toward our struggle," he said.

Henry Siegman, executive director of the American Jewish Congress, rose to say Mandela's response displayed "a certain degree of amorality" by ignoring human-rights violations in other nations. But Mandela did not back off.

"Firstly, we are a liberation movement, which is fully involved in a struggle to emancipate our people from one of the worst racial tyrannies the world has seen," he said. "We have no time to be looking into the internal affairs of other countries."

At another point, he said: "We identify with the PLO because just like ourselves, they are fighting for the right of self-determination . . . . To think that because Arafat is conducting a struggle against Israel that we must therefore condemn him, we can't do it. It is just not possible."

Mandela said he has never doubted Israel's right to exist "within secure borders" but said the Jewish state must return all of "the territories they conquered from the Arab world." He also said that Jews were active in the ANC, that a Jew had trained him as a lawyer and that Jewish attorneys had defended accused blacks in South Africa.

The pro-Mandela audience frequently interrupted with lusty cheers, particularly when Mandela sparred with Koppel. When Koppel asked why the Bush administration should not recognize the fact that de Klerk, who took office last fall, has taken such important steps as freeing Mandela in February and lifting a ban on the ANC, Mandela said:

"Mr. Koppel, you are entirely misinformed. In the first place, the ANC ought never to have been banned. Secondly, my comrades and I ought never to have been sent to prison . . . . You are crediting Mr. de Klerk for rectifying his own mistakes."

The son of a royal family of the Thembu tribe, Mandela said the ANC bears no responsibility for warring between black factions in South Africa that has claimed 4,000 lives. He said de Klerk was tolerating the unrest "because you believe you can crush your Enemy No. 1, the ANC."

Mandela also urged U.S. officials not to try to shore up de Klerk's political standing, saying that would make de Klerk seem to be a "puppet . . . . Please, whatever you do, don't do that . . . . You are playing with fire . . . . That is what the right wing exactly wants. You will destroy him."

Mandela smoothly sidestepped questions that he did not choose to answer. When a rival black South African leader, in a pretaped interview, asked why Mandela did not negotiate to stop the factional violence, Mandela said: "I do not think it correct for me to wash our dirty linen in a foreign country."

Mandela's day began when a dozen security guards accompanied him on a 20-minute morning stroll from Gracie Mansion, where he spent the night, to the East River.

Mandela, his wife Winnie, Mayor David N. Dinkins and Jesse L. Jackson then left Manhattan's Upper East Side for Riverside Church in Harlem, where Mandela told 150 religious leaders that American churches have been "in the front line of the struggle" against apartheid. The clergymen handed Mandela a check for $200,000.

The 2,500 guests packing pews of the cavernous, neo-Gothic cathedral gave Mandela and his wife a thunderous ovation, many raising their arms in the clenched-fist salute and some women making the high-pitched warbling ululations often heard at demonstrations in South Africa.

Mandela made an eloquent plea for continued U.S. sanctions against the de Klerk government.

"We have yet to have full evidence that Mr. de Klerk is prepared for the transition to full democracy," he said. "To lift sanctions now . . . would be a serious political error. It could plunge us back into the darkness from which our country is painfully struggling to emerge."

In a loud, clear voice, Mandela declared: "In the words of the prophet Isaiah, we have risen up as on the wings of eagles . . . . Our people have hungered and thirsted for their liberation. Many have died. Many thousands have known exile, been jailed, banned and restricted."

Jackson, addressing Mandela and other ANC officials, said, "We approach you with a sense of shame. We have not done enough. The CIA and our government joined with South Africa to arrest our brothers and expose them. Please forgive us for the sins of our government."

At 7:30 p.m., a tired-looking Mandela and his wife boarded a platform at Adam Clayton Powell and Martin Luther King boulevards while people danced to the echo of African drums. The crowd exploded when Winnie Mandela called Harlem "the Soweto of America" and said that, if negotiations in South Africa break down, "we want you to be there if we go back to the bush and fight against the white man."

Nelson Mandela recited an honor roll of American civil-rights leaders, but reaction was more restrained as he breezed through his prepared remarks.

Staff writers Kenneth J. Cooper and Gwen Ifill and special correspondent Laurie Goodstein contributed to this report.