Sweden observed a minute of silence Monday on a national day of mourning for the four people killed and 15 wounded in a truck attack last week, while the suspect's name emerged in court papers and the U.N. Security Council condemned the rampage.
Swedish royalty, foreign diplomats and politicians were among the crowds gathered for a noon observance outside Stockholm City Hall, where Prime Minister Stefan Lofven said "the whole of Sweden" sympathized with the families and friends of the victims.
The suspect, named in court documents Monday as 39-year-old Uzbekistan national Rakhmat Akilov, allegedly drove the truck into a crowd outside an upscale department store in central Stockholm on Friday. The four people killed included two Swedes, a British man and a Belgian woman.
The victims' home countries suffered "horrendous acts of terrorism, but we have also seen the strength and determination and power of our democratic societies," Lofven said.
"We will never surrender to terror. We will get through this together," he said.
The U.N. Security Council condemned "the barbaric and cowardly terrorist attack" in the strongest terms on Monday and reiterated that "any acts of terrorism are criminal and unjustifiable, regardless of their motivation, wherever, whenever and by whomsoever committed." The council underlined the need to bring the perpetrators to justice.
The White House said in a statement that U.S. President Donald Trump called Lofven on Sunday and "the two leaders agreed to maintain and strengthen the already close partnership between the United States and Sweden in the global fight against terrorism."
In February, Trump surprised Swedes when he suggested Sweden could be the next European country to suffer the kind of extremist attacks that have devastated France, Belgium and Germany.
Police arrested a man on Friday night after the attack that was carried out with a hijacked beer truck, but only identified him as a 39-year-old Uzbek whose Swedish residency application was rejected last year. He is being held on suspicion of terrorist offenses.
Swedish police chief Dan Eliasson told a news conference that "we are sure that we have the driver of the truck," and Stockholm regional police commander Jan Evensson said that suspicions against the Uzbek suspect "had grown stronger" during questioning.
"He will sit behind bars for the rest of his life," Evensson said.
Police have arrested another man in the case but gave no details. Four others, who were held for questioning, have been released, police said.
On Monday, the prosecutor's office requested a formal detention order to continue Akilov's arrest. The hearing was scheduled for Tuesday at the Stockholm District Court.
Friday's attack shocked Swedes who pride themselves on their open-door policies toward migrants and refugees, and many expressed fears that something had gone badly wrong.
In 2015, a record 163,000 asylum-seekers arrived in the country — the highest per capita rate in Europe. The government responded by tightening border controls and curtailing some immigrant rights.
Officials have acknowledged the difficulty of keeping tabs on asylum-seekers who have been ordered to leave the country after their applications were turned down.
Police said the truck attack suspect was known for having been sympathetic to extremist organizations. But Eliasson said "there was nothing in the system that indicated that he would do anything like what happened on Friday."
"If we would have had knowledge, information, of course we would have acted differently. But no such information (was) in the system and that's very important to note," he said.
Eliasson conceded there were "a huge number of persons" who have been denied asylum and the right to stay in Sweden, describing it as a problem.
"I think we have the same problem in all European countries," he said. "It is difficult to return people to some countries (which) will not either accept the return of their own citizens or, if we return them by force, they will be subject maybe to punishment in those countries."
Swedes have poured into downtown Stockholm since the attack, building a wall of flowers and scribbling notes on sidewalks and wooden boards in memory of the victims, and encouraging people to refrain from despair or hate.
Earlier Monday, some gathered outside the Ahlens department store, among them John Holmstrom, an employee who said he'd been at work just two hours before the attack.
"It's been a real shock, all this week and everything around this weekend about this accident," Holmstrom said. "I know a lot of people that were really, really close to getting hit by the truck."
This story has been corrected to show that the last name of Sweden's national police chief is Eliasson, not Danielsson.
Huuhtanen reported from Helsinki. Associated Press Writer Edith M. Lederer contributed from the United Nations in New York.