MADRID: Forensic scientists have begun exhuming the bodies of 128 victims of the Spanish Civil War from the former mausoleum of General Francisco Franco near Madrid, the government said on Monday.

The exhumation, which is being carried out as an election campaign heats up, is the first involving people whose bodies were moved from other parts of Spain after the 1936-1939 war and reburied without their families' consent in a monument built by Franco in the Valley of Cuelgamuros, formerly known as Valley of the Fallen.

It is likely to make Franco's four-decade dictatorship, which still divides Spanish society, a topic of passionate discussion as Socialist Prime Minister Pedro Sanchez seeks reelection.

The remains of some 34,000 people, many of them victims of Franco's regime, are buried anonymously in the crypt of the basilica carved into a mountainside northwest of Madrid. Relatives have been fighting for years to give their loved ones a burial under their own names and near their families.

"It's justice for all those families who have asked for the remains of their loved ones to be recovered," Felix Bolanos, the minister in charge of overseeing exhumations, said on RTVE. "By the way it's families from both sides. I think it is pure humanity".

Passing a law that makes it possible for relatives to identify victims who are buried in about 2,400 unmarked mass graves around Spain was one of the first policies implemented by Sanchez when he came to power in 2018.

The rival conservative People's Party has opposed the so-called "Law on Democratic Memory" and vowed to repeal it if it wins power in the July 23 vote.

"It's a bit more of the same from the government - the use not only of institutions but of Spain's history," Isabel Diaz Ayuso, president of the Madrid region, said on Monday. "I can't do anything more than condemn it but I don't want to say anything more because I'm convinced that they want us to do it to get drawn into their campaign."

The process of identifying the remains could take weeks or months, meaning the results will probably be published after the election.

The government said a team of 15 forensic investigators had begun a first phase by attempting to identify 18 bodies claimed by relatives located in one section of the crypt. Samples will be sent to the National Institute of Toxicology and Forensic Sciences in Madrid.

"It's not an easy task and there's no equivalent precedent anywhere else in the world," the Ministry of Justice said in a statement.

The remains of Jose Antonio Primo de Rivera, founder of Spain's fascist Falange movement that supported the Franco regime, were dug up and removed from the mausoleum in April.

That followed the exhumation of Franco's body in 2019 as part of a plan to convert the complex, which includes 150-metre-high (490-foot-high) cross and became a site of pilgrimage for his supporters, into a memorial to the 500,000 people killed during the civil war.

The Association for the Reparation of Historic Memory, an NGO representing victims of Franco, said on Twitter that while Franco's family was able to carry out his coffin on their shoulders, the families of his victims had to find out through the media that their relatives were being exhumed.

Spain transitioned to democracy following Franco's death in 1975.