By TIM WEINER

MEXICO CITY, June 4 — A former Cuban diplomat and spy who was jailed in Havana after seeking political asylum here, has asked
President Vicente Fox to help him regain his freedom.

The envoy, Pedro Riera Escalante, former Cuban consul in Mexico City, broke with his government and formally sought political asylum in the fall.
But he was forcibly deported by Mexico in October, two months before Mr. Fox took office.

In Cuba, Mr. Riera was sentenced by a military court to six years in prison for illegally leaving Cuba.

In a letter dated May 18, the day he was sentenced, and made public here today, Mr. Riera asked Mr. Fox to intercede with President Fidel
Castro and said he had been kidnapped and illegally deported by Mexican immigration authorities in violation of the Universal Declaration of
Human Rights.

"I have been threatened with death if I make statements affecting the Cuban government and if I take a political stand against it," the letter said.

He said in an interview, barely an hour before his arrest here, that he had become disillusioned with Cuba's government and feared for his life if he
fell into the hands of his old intelligence service. He said the service, once highly effective, now served primarily to protect Mr. Castro's power.

Before his arrest, in conversations in Mexico City with human-rights advocates and two reporters, Mr. Riera, 49, said he started working for the
Cuban intelligence service in 1973. He was in Europe, Africa and Mexico and ran operations aimed at discrediting or disrupting the Central
Intelligence Agency, he said.

He told the Mexican human rights advocates who represented him that his intelligence work here, under cover as a diplomat from 1986 to 1991,
included recruiting and managing agents, among them officials from the party that governed Mexico for decades, who collaborated with the Cuban
government. That has raised the question of whether he was ordered deported by officials who were sensitive to the possible exposure of past or
present Cuban agents in the party, the PRI.

Officials from the Interior Ministry, which handles state security, said in October that Mr. Riera was here illegally and that his rights had been
respected during his brief detention because Cuban Embassy officials were present while he was interrogated. Mr. Fox's government, which took
power in December, has said little about the case.

Mr. Riera pleaded guilty before a three-judge military court in Cuba after a one-day trial to charges of using a false Mexican passport and tourist
visa and of paying $2,000 in cash and goods to contacts at the international airport in Havana to leave Cuba. Four other people, including an
officer of the Cuban Interior Ministry and an immigration official, are accused of helping him.