EXICO CITY, Nov. 8 — Faced with mounting pressure from international human rights groups, President Vicente Fox ordered the release of two ecologists today after they had been tortured by soldiers and jailed for leading a campaign to stop the destruction of forests in the Pacific Coast state of Guerrero.

The ecologists, Rodolfo Montiel and Teodoro Cabrera, who were considered prisoners of conscience by Amnesty International, walked out of a jail in the town of Iguala, in Guerrero, shortly after noon. The two leaders of the Organization of Peasant Farmer Ecologists, who had won many international awards for their work, were rushed away by car. Later in the afternoon, they addressed a small crowd of reporters.

Mr. Montiel, his voice barely rising above a whisper, reiterated his commitment to the fight for the forests. "I only want to say that it seems now, little by little, we can begin to trust in justice," he said. "This is a first step, but we cannot stop here."

In a terse statement to the press, President Fox said, "With this, we show by our actions, my government's commitment to the promotion and observance of human rights in our country."

The government's decision to release the two leaders came less than a month after the assassination of a high-profile human rights attorney who had defended them. The lawyer, Digna Ochoa, 37, was shot execution style in her office here on Oct. 19. She had received numerous death threats, and was once assaulted in her home by men in ski masks. Investigators have linked Ms. Ochoa's murder to her work on behalf of the ecologists, and have said that "lines of investigation" may link the murder to the military.

In the past week, Mexico has been alarmed by new death threats against several other human rights activists. Yesterday, lawyers for Mr. Montiel and Mr. Cabrera expressed concern for the safety of their clients.

"It is hard to tell whether or not the threats are serious," said Sergio Aguayo, one of the human rights defenders who was listed on a death threat last week. "It could have come from some crazy person. But what worries me is that it could have come from some powerful forces trying to destabilize the Fox government."

The lawyers for the two ecologists also said today that they would continue to seek prosecution for the soldiers accused of torturing Mr. Montiel and Mr. Cabrera. One lawyer, Mario Patron, also said that Ms. Ochoa's assassination might eventually be linked to early speculation that the ecologists were going to be released.

President Fox, the first opposition politician to win the presidency in seven decades, had promised to impose the rule of law and end systematic abuses by government security forces.

He had also promised to create a truth commission to investigate the most important government abuses in recent history and to abide by international human rights accords. The president had also indicated his willingness to seek the release of Mexico's most prominent political prisoners.

Since Ms. Ochoa's assassination Mr. Fox has argued that it takes time to dismantle a 71-year-old system of corruption and injustice. But human rights activists and government officials said that Mr. Fox's promises have been stalled by forces from within his own cabinet led in particular by the Mexican military and Attorney General Rafael Macedo de la Concha.

"I find all this troubling," said Eric Olson of the Washington Office on Latin America, a human rights group. "When you ask President Fox whether he is in favor of ending torture, he says all the right things. But then when it comes to stepping on people's toes, and making things happen, he backs away. And it makes me wonder whether he has a gut- level understanding of these issues."

Signs of internal disputes within the government have become evident in the cases of political prisoners like Mr. Montiel and Mr. Cabrera, who were detained on weapons and drug charges. Before they were arrested in May 1999, the men had organized a series of roadblocks to stop wildcat logging by local political bosses.

Human rights groups, including the government's own National Human Rights Commission, had contended that Mr. Montiel and Mr. Cabrera were illegally detained by the military and tortured into signing false confessions. Yet human rights investigators said that in an appeal earlier this year, the Mexican military submitted a brief that denied the accusations of torture.

Officials at Amnesty International said that the Mexican attorney general's office had also filed briefs that argued against the release of Brig. Gen. José Francisco Gallardo, who was convicted of corruption despite inconclusive evidence. Human rights groups contend that General Gallardo was jailed because he spoke out about military abuses.

Attorney General Macedo, who is also an army general, was in charge of military justice before he was appointed to Mr. Fox's cabinet. He was also involved in defending the army against human rights investigations in the cases of the ecologists and General Gallardo.

Human right activists speculated that General Gallardo could be released in the days ahead.

Mexican officials said that President Fox had been seeking the release of Mr. Montiel and Mr. Cabrera for months. They said that the president had wanted the release to come through legal processes rather than through presidential decree. "He wanted to help strengthen the judicial system, not short-circuit it," said Foreign Minister Jorge G. Casteñeda.

But after Ms. Ochoa's murder, officials said, Mr. Fox decided that the ecologists' release could not wait.