BARCELONA, Spain (CNS) — Nearly one month after a devastating terrorist attack in Barcelona, police evacuated the city’s most renowned church, La Sagrada Familia, fearing a possible bomb threat.

The Catalan police force, known as the Mossos d’Esquadra, carried out an evening anti-terrorism operation Sept. 12 after receiving reports of a suspicious vehicle parked outside the unfinished basilica designed by Spanish architect Antoni Gaudi.

An hour after the evacuation, police tweeted that “the situation has normalized in Sagrada Familia. It is a false alarm.”

The city has been on high alert after a van mowed down pedestrians Aug. 17 on Barcelona’s famous Las Ramblas street, killing 13 people. Five suspects were killed by police and other members of what authorities described as a 12-man terrorist cell were being sought.

The Islamic State took credit for the attack.

One of the suspects involved in the attack, 21-year-old Mohamed Houli Chemlal, testified in a Madrid court Aug. 21 that the basilica was among several monuments targeted by the cell.

Despite the false alarm, Catalan police encouraged people who find themselves “in a situation like yesterday at Sagrada Familia, who receive unverified information or have questions” to follow their @mossos account on Twitter.