By Emily Green (Reuters) -El Salvador President Nayib Bukele's drive to consolidate his grip on power and crack down on critics and humanitarian organizations has forced a leading human rights organization to suspend operations in the country and go into exile, the group told Reuters. Cristosal, which was founded by Anglican bishops 25 years ago and came to prominence for its investigations into corruption in the Bukele government, has pulled 20 employees out of the country in recent weeks. The group told Reuters it has just one employee left in El Salvador: Ruth Lopez, its anti-corruption and justice director, who has been jailed since May on corruption charges. Cristosal's decision to evacuate its staff has not been previously reported. The human rights group said its decision represents a turning point in Bukele's three-year state of emergency, with many journalists and other rights groups also deeming it unsafe to continue operating there. "When it became clear that the government was prepared to persecute us criminally and that there is no possibility of defense or impartial trial, that makes it unviable to take those risks anymore," said Noah Bullock, executive director of Cristosal, who spoke to Reuters from Guatemala. The government brought the case against Lopez under seal, prompting her to call for a public trial. Reuters could not independently establish the charges against her. A spokesperson for El Salvador's attorney general's office didn't respond to requests for comment about why the case against Lopez is sealed, and whether officials consider her a danger. A spokesperson for Bukele did not respond to a request for comment about the pressure on human rights organizations. Since imposing a state of emergency in March 2022, Bukele has suspended constitutional rights, curtailed freedom of the press and undermined judicial independence. Human rights groups say thousands of innocent people have been swept up in his gang crackdown, which has resulted in the arrests of more than 85,000 people. Bukele has said such drastic measures were needed to eliminate the gangs' hold over the country. Homicides have fallen more than 90% since he took office, according to government figures. Despite international criticism, Bukele remains extremely popular in El Salvador, with a nearly 85% approval rating, according to a survey released in June by the Jesuit Central American University. But there are signs of unease: Nearly 60% of those surveyed said it is very likely a person or institution could suffer negative consequences for expressing criticism of the president or government. A law enacted in May makes it practically impossible for many civil rights organizations with international funding to operate, according to people working at these institutions. The law requires individuals and organizations that receive international funding to register as "foreign agents" and places a 30% tax on every financial transaction involving foreign funds. Failure to comply could expose groups to criminal prosecution under anti-money laundering laws. Bukele, who was elected president in 2019, devoted a significant portion of his state of the union address last month to criticizing journalists and human rights groups. He said human rights groups receive "millions each year to peddle misery and spread violence." LAWYERS AND RIGHTS GROUPS FLEE At least four human rights groups in addition to Cristosal have withdrawn staff for security reasons, Bullock said. Reuters was able to confirm departures from two of the groups. The arrest of Lopez, Cristosal's well-known anti-corruption and justice director, marked a significant escalation in Bukele's attack on critics, rights groups say. Since May, about 60 lawyers and human rights activists have fled, according to Salvadoran human rights lawyer Ingrid Escobar, who left the country after what she described as a campaign of police harassment. At least 40 journalists have also left since May due to police harassment, surveillance and fear of imminent arrest, according to the Association of Journalists of El Salvador. In a speech before the United Nations General Assembly last year, the Salvadoran president declared that freedom of expression is protected and "we don't arrest people for their own ideas." Last month, authorities arrested constitutional lawyer Enrique Anaya on charges of money laundering. An outspoken critic of the president, Anaya had called Bukele a dictator on live television. Like Lopez, Anaya's case is sealed, and a judge has ordered him to remain in prison as proceedings continue. The spokesperson for the El Salvador attorney general's office didn't respond to a request for comment about the case. Angelica Carcamo, director of the Central American Network of Journalists, said Anaya's case persuaded her that it wasn't safe to return to El Salvador. She said she fled after a home security camera captured images of armed soldiers milling outside. Reuters couldn't independently confirm this. "As long as there are no guarantees of protection for the press or those of us who practice journalism or defend human rights, it is not advisable to return," Carcamo said. Cristosal's Bullock said Bukele has been emboldened by his alliance with President Donald Trump, cemented by the agreement reached in March to house 238 Venezuelans deported from the United States in a maximum-security prison. Bukele also resisted the return of Kilmar Abrego Garcia, an imprisoned Salvadoran man wrongfully deported by the Trump administration. Bukele has denied Abrego Garcia's claims that he was tortured in El Salvador's mega-prison. During Bukele's visit to the White House in April, Trump said Bukele is "one hell of a president" and "doing incredibly for your country." (Reporting by Emily Green in Mexico City; Editing by Stephen Eisenhammer and Suzanne Goldenberg)