SAN SALVADOR, El Salvador (AP) — Huge crowds are expected at Saturday's ceremony to beatify Roman Catholic Archbishop Oscar Romero, who was cut down by an assassin's bullet 35 years ago and declared a martyr for his faith this year by Pope Francis.

It is the first step toward possible canonization, although many of the 260,000-plus faithful anticipated to fill the capital's Savior of the World Plaza already credit him with miracles and refer to him as "Saint Romero of the Americas."

In life, Romero was loved by the poor whom he made it his mission to defend and loathed by conservatives who considered him too close to left-leaning movements in the tumultuous years ahead of El Salvador's 1980-92 civil war.

Romero was celebrating Mass in a cancer hospital chapel on March 24, 1980, when he was shot through the heart by a sniper who apparently fired from a car outside. The day before, Romero had delivered a strongly worded admonition to the U.S.-backed military to stop repressing civilians.

The trigger man has never been identified, and nobody has ever been prosecuted for the killing. Alleged paramilitary death squad leader Roberto d'Aubuisson, who was named by a U.N. truth commission after the war's end as the mastermind of the assassination, died in 1992 having maintained his innocence to the end.

Romero's beatification was held up for years by church politics until Pope Benedict XVI "unblocked" the case in late 2012, after it was determined he had not been an adherent of revolutionary liberation theology as many claimed.

Saturday's ceremony constitutes official church approval of Romero's legacy, even if some conservatives in the Vatican and Salvadoran society still view his memory with distaste.

The event was scheduled to begin with a procession from the cathedral in downtown San Salvador, where Romero's remains lie in a basement crypt, to the plaza 2.5 miles (4 kilometers) to the west.

Cardinal Angelo Amato, the prefect of the Vatican's saint-making office, and the current archbishop of San Salvador, Luis Escobar Alas, planned to preside over a ceremony that would include a homily and a reading of the letter designating Romero as blessed.

A huge stage was erected in recent days beneath the square's 60-foot-tall (18-meter-tall) monument depicting Christ atop a white pillar and blue globe. An urn there contains the shirt that Romero was wearing when he was shot.

Officials closed off about 2 square miles (5 square kilometers) of streets nearby to accommodate the expected crush of pilgrims, many of them bused in from the countryside, and the hundreds of vendors selling commemorative T-shirts, key chains, bags, bracelets and coffee cups for $2 to $5 as well as copies of documentaries and movies inspired by Romero's life.

Authorities set up 27 giant screens for the benefit of those far from the stage and deployed 3,700 police and soldiers to provide security. Hotels in the capital were at capacity, and officials predicted the event would generate $31 million in economic activity.

Celebrations were also planned in Los Angeles, which is home to about 360,000 people of Salvadoran origin. Many of them arrived in the 1980s fleeing the Central American nation's civil war, in which at least 75,000 people died and 12,000 more disappeared.