Murdered Salvadoran Archbishop Oscar Romero has edged closer to sainthood after a panel of theologians voted unanimously to recognise him as a martyr.

According to the Catholic News Service, the Italian newspaper Avvenire reported yesterday that the panel advising the Vatican's Congregation for Saints' Causes declared that the archbishop had been killed "in hatred for the faith".

Romero was killed on March 24, 1980, as he celebrated mass in a hospital in San Salvador. His death came the day after he had publicly called for soldiers to lay down their guns and end government repression. No one has been charged or convicted of his murder, though a death squad led by former Major Roberto D'Aubuisson is suspected of the killing.

Originally chosen as a conservative figure, he became increasingly horrified by the actions of the Salvadoran government during the country's vicious civil war and spoke out against poverty, social injustice, assassinations and torture.

His sainthood cause was opened in 1993 but stalled over political questions: Pope Benedict XVI told reporters in 2007 that the archbishop was "certainly a great witness of the faith" who "merits beatification, I do not doubt." But he said some groups had complicated the sainthood cause by trying to co-opt the archbishop as a political figure.

Romero's cause will now go to the Congregation for Saints' Causes, which advises the Pope on beatifications. Pope Francis has previously signalled his support for Romero's cause.