Although much about Thursday’s terrorist attack in Barcelona, Spain, in which a van veered into a crowd and reportedly left as many as 13 people dead and more than 50 injured, remains unclear, Catholic leaders in the country and around the world have been united in condemning the incident.

“The Holy Father has learned with great concern what’s happening in Barcelona,” said a Vatican statement on Thursday released by Pope Francis’s spokesman, American journalist Greg Burke.

“The pope is praying for the victims of this attack, and desires to express his closeness to the entire Spanish population, in particular to the wounded and to the families of the victims,” Burke’s statement read.

“I condemn the attack committed in Barcelona, with dead and wounded, which fills our hearts with pain and solidarity with the victims,” said retired Cardinal Lluís Martínez Sistach, who led the Archdiocese of Barcelona from 2004 to 2015, in a tweet sent on Thursday in the wake of the violence.

Around the same time, Auxiliary Bishop Sebastián Taltavull of Barcelona tweeted out, “I condemn the attack committed in Barcelona, commending the souls of the victims [to God] and am accompanying their relatives in prayer.”

Cardinal Juan José Omella of Barcelona, who took over from Sistach in 2015, announced he was suspending a set of spiritual exercises in which he was participating in order to “return to Barcelona and be with his people in this moment of pain,” according to a tweet from the official archdiocesan account.

Father José María Gil Tamayo, the Secretary General of the Spanish bishops’ conference, said, “We’re following with concern and prayer the situation of the victims of this massive outrage on the Ramblas,” referring to the central section of Barcelona where the attack took place.

Using his own Twitter account, Gil Tamayo expressed “our solidarity with the victims and with Barcelona.”

Local police said late Thursday Barcelona time that one death had been confirmed so far, with 32 injured, 10 seriously, but Spanish media cited police sources as saying the death toll was much higher.

Despite earlier reports that a hostage situation had developed in a nearby bar after the attack, Barcelona said there was no such standoff, and also announced late Thursday they had detained a suspect in the incident. Media identified that individual as Driss Oukabir, A Spanish resident of Moroccan descent.

Later, police said they had arrested two other individuals, though details were not available.

Politicians, civic leaders, even sports stars and celebrities around the world also addressed the Barcelona attack on Thursday. U.S. President Donald Trump tweeted, “The United States condemns the terror attack in Barcelona, Spain, and will do whatever is necessary to help. Be tough & strong, we love you!”

Even outside the immediate Barcelona area, other Spanish bishops offered their own statements of concern.

“Moved by the attack on the Rambla de Barcelona, I share the suffering and am praying for the victims, their families and all citizens,” said Bishop Francisco Pardo of Girona.

With a photo labeled “Pray for Barcelona,” Bishop José Ángel Saiz Meneses tweeted: “Terrorist attack in the Ramblas in Barcelona. Massive outrage. At least 13 dead and 20 injured. Prayer and solidarity with the victims.”

Spanish police are treating the attack as a terrorist incident. Later Thursday, an ISIS-related news agency issued a statement claiming that the perpetrators were “soldiers of the Islamic State.”

In the United States, Bishop Oscar Cantú of Las Cruces, Chairman of the U.S. Conference of Catholic Bishops Committee on International Justice and Peace, issued a statement in response to the Barcelona attack.

“Once again, an act of terror has taken more than a dozen lives and injured scores of others.  The United States Conference of Catholic Bishops unequivocally condemns this morally heinous act and places itself in solidarity with the people of the Archdiocese of Barcelona and Spain at this terrible time of loss and grief,” Cantú said.

“Terrorist attacks on innocent civilians can never be justified,” he said. “To directly attack innocent men, women and children is utterly reprehensible.”

“May God comfort the afflicted and convert the hearts of those who would perpetrate such acts,” Cantú said.