On Thursday afternoon, a van veered onto Barcelona's famous Las Ramblas promenade, killing 14 people and injuring around 100 others. Hours later, Spanish police responded to a second terrorist attack when they fatally shot five people in Cambrils, south of Barcelona.
As news of the attacks unfolded, world leaders and political figures shared their support with those affected by the violence. However, President Donald Trump has been criticized for his response to the incident, which lauded the alleged tactics of General John Pershing in dealing with Islamic extremists in the Philippines at the turn of the last century.
Trump tweeted on Thursday that people should "study what General Pershing of the United States did to terrorists when caught. There was no more Radical Islamic Terror for 35 years!"
Gen. John Pershing, who died in 1948, served as commander of the American Expeditionary Forces during World War I. And this isn't the first time Trump has referenced the US army officer.
During the presidential campaign, he told a widely discredited story that Pershing had halted Muslim attacks in the Philippines by shooting rebels with bullets dipped in pigs' blood. Pork is taboo for Muslims, but that story has been widely debunked by historians as unsubstantiated or exaggerated.
While Trump was not specific about the tactics he was referring to, many critical commentators believe the tweet revived the specific story about Pershing and the bullets dipped in pigs' blood that he told during the campaign.
Others have said the tweet also highlights the president's "double standard" on terrorism. Within hours of the Barcelona news, the president condemned terrorism in his initial tweet which said the US "will do whatever is necessary to help." But this prompted further scrutiny over his slow response to the violence in Charlottesville,Virginia, when he reverted to blaming "many sides" for the backlash which left one woman dead and several injured.
Trump's stance on the far-right rally in Charlottesville has been widely criticized by political figures around the world. Following his remarks at a press conference on Tuesday, when he once again blamed "both sides," Theresa May has faced fresh calls to delay the president's state visit to Britain.