US president Joe Biden has condemned a tense 11-hour hostage standoff at a synagogue in Texas on Saturday as “an act of terror”, as the FBI named the armed assailant as Malik Faisal Akram, a 44-year-old British national. Akram was pronounced dead after the FBI stormed the Congregation Beth Israel synagogue in the Dallas suburb of Colleyville on Saturday evening. All four hostages survived the siege and were unharmed, according to local police. UK security sources confirmed to the Guardian that the suspect had been a resident of Blackburn in Lancashire. This was later confirmed in a statement by Greater Manchester Police. The standoff began during a Saturday morning service at the Reform synagogue in the affluent city of around 26,000 residents. The service was being live streamed on Facebook when a man with a British accent could be heard shouting off camera. The feed was eventually cut hours later and police were called at around 10.41am. One male hostage, believed to be the synagogue’s rabbi, was released at around 5pm as negotiations continued throughout the day. Armed FBI officers stormed the building and rescued the three remaining hostages at around 9pm, authorities said. Details of the manner of Akram’s death have not been released. Counter terrorism police in London confirmed they were liaising with their US counterparts on Sunday as the FBI confirmed an active investigation but added they believed Akram had acted alone. Speaking to reporters on Sunday, president Biden described the incident as “an act of terror” and confirmed he had been briefed by the US attorney general, Merrick Garland. Asked by reporters how Akram could have procured weapons in the US, Biden said he did not have all the facts of the case but “the assertion was he got the weapons on the street. He purchased them when he landed.” It was not immediately clear how long Akram had been in the US before carrying out the attack. The US Department of Homeland Security did not immediately respond to questions about when or where Akram entered the country, and on what visa. The president said he had contacted the synagogue’s rabbi, Charlie Cytron-Walker, who posted an account of the incident to Facebook on Sunday. “I am grateful that we made it out,” Cytron-Walker wrote. “I am grateful to be alive.” The suspect became “increasingly belligerent and threatening” toward the end of the standoff, Cytron-Walker said in a statement released later Sunday. He said security training that his congregation has received over the years had helped him and the other hostages get through the ordeal, adding that without it, “we would not have been prepared to act and flee when the situation presented itself”. Earlier Sunday, Biden praised the “courageous work” of law enforcement officials who responded to the scene and sent “love and strength” to the synagogue’s worshippers and to members of the Jewish community. FBI special agent in charge, Matt DeSarno, said the hostage taker was specifically focused on an issue not directly connected to the Jewish community, and there was no immediate indication that the man was part of any broader plan. But DeSarno said the agency’s investigation “will have global reach”. During the live stream, Akram could be heard demanding the release of Aafia Siddiqui, a Pakistani neuroscientist suspected of having ties to al-Qaida, who was convicted in 2010 of trying to kill US military officers while in custody in Afghanistan. Siddiqui is in federal prison in Texas serving an 86-year sentence. The hostage-taker referred to Siddiqui as his “sister” on the livestream, but John Floyd, board chair for the Houston chapter of the Council on American-Islamic Relations – the nation’s largest Muslim advocacy group – confirmed Siddiqui’s brother, Mohammad Siddiqui, was not involved. Dramatic footage of the siege’s end, filmed by local news, depicted three people sprinting from the synagogue, followed briefly by a man who appeared to be holding a gun, who then retreats back inside the building. Dozens of armed officers then storm inside, a loud bang followed by a shots are then heard. On Sunday the British foreign secretary, Liz Truss, condemned the incident in a statement posted on Twitter. “My thoughts are with the Jewish community and all those affected by the appalling act in Texas. We condemn this act of terrorism and antisemitism,” Truss said. She added: “We stand with US in defending the rights and freedoms of our citizens against those who spread hate.” Shortly after Akram was named as the hostage taker, a post on the Blackburn Muslim Community Facebook page was uploaded, purportedly written by his brother Gulbar. The post stated that Akram “was suffering from mental health issues” but the family were “confident that he would not harm the hostages”. It stated that family members had been sat in an incident room all night liaising with Akram, the FBI and hostage negotiators. The post claimed that Akram released all the remaining three hostages before “a firefight has taken place and he was shot and killed”. “There was nothing we could have said to him or done that would have convinced him to surrender,” the post states. It adds: “We would also like to add that any attack on any human being be it a Jew, Christian or Muslim etc is wrong and should always be condemned.” The Guardian has not confirmed the veracity of the post, but a written statement with the same words was reported by Sky News. The incident prompted statements of solidarity from the Jewish community. “Today we have felt the all too familiar sinking in our hearts, the outrage and horror of witnessing yet another antisemitic attack on a synagogue on Shabbat,” said Stosh Cotler, CEO of Bend the Arc: Jewish Action in a statement. “We worry that in the days ahead there will be those who try to use our community’s pain and trauma to fuel division or incite violence against other communities – we will not let them. We will reject any attempt, rooted in anti-Muslim bigotry, to hold an entire community responsible for the actions of one individual.” Zara Mohammed, secretary-general of the Muslim Council of Britain, condemned the hostage-taker’s actions. He said: “The act is all the more reprehensible since it was instigated at a place of worship where Jews were targeted. This was, quite simply, a hate crime and an act of antisemitism. We are thankful that the hostages are unharmed. Though some may seek to exploit such incidents for divisive ends, we must double our resolve to remain united against such hatred.” The incident marked the latest in a spate of attacks on Jewish places of worship in the US. In October 2018, a gunman murdered 11 worshipers at the Tree of Life Synagogue in Pittsburgh. In 2019, one worshipper was killed and three injured at the Chabad of Poway synagogue in California. Incomplete FBI hate crimes data for 2020 indicated antisemitic hate crimes constituted the majority of targeted attacks on religious groups in the US with 676 recorded incidents.