Ruth Elonora López defends the Venezuelan immigrants who have deported from El Salvador by U.S. President Donald Trump’s administration.

A prominent human rights lawyer, known for defending immigration, has been arrested in El Salvador in a tough anti-immigration policy by U.S. President Donald Trump.

Ruth Eleonora López, 47, a senior figure in the rights group Cristosal and a voice critic for Trump ally El Salvador President Nayib Bukele, was detained late Sunday.

The arrest was confirmed by the country's attorney general's office, which was accused of Lopez of embezzling state funds during the El Salvador election court more than a decade ago.

"Neither her family nor the legal team managed to find out her whereabouts," Christo Salles said in a statement, declining to disclose her location or allowing attorneys to "blatantly violate due process" rights to access.

The group said her arrest was "a serious concern about the increased risks faced by El Salvador human rights defenders".

Lopez has publicly criticized the government for mass incarceration of alleged gang members, many of whom have not been charged.

Cristosal, one of Latin America’s most prominent human rights groups, assisted El Salvadorian families in trapped in Buckley’s security policies and the more than 250 Venezuelan immigrants deported to El Salvador under the Trump administration.

Buckley called himself “the coolest dictator in the world” and has established close ties with Trump, who earlier this year said El Salvador is ready to bring American prisoners into last year’s sprawling super-jail.

In March, Trump rarely used wartime powers to send dozens of Venezuelans to El Salvador without trial, allegations were linked to the Tren de Aragua gang, a charge denied by their families and lawyers.

The U.S. Supreme Court on Friday banned the Trump administration from quickly resuming the rapid deportation of Venezuelans under the 1798 Alien Enemy Act.

Cristosal reported in April that police entered its offices at a press conference to photograph and photograph journalists and staff - part of what observers said was a wider harassment and intimidation campaign against civil society organizations and independent media.

Lopez is recognized by the BBC as one of the most inspiring and influential women in the world for her commitment to justice and the rule of law.

A joint statement signed by more than a dozen rights groups, including Amnesty International and Human Rights Watch, demanded her immediate release.

"The state of exception in El Salvador is used not only to address gang-related violence, but also to address critical voices," the statement said.

It added: “In recent years, authoritarianism has increased as President Nayib Bukele undermines institutions and the rule of law and persecutes civil society organizations and independent journalists.”