Rakhmat Akilov, a 39-year-old Uzbek national, is in custody on suspicion of mowing down a crowd on a busy street in the Swedish capital, killing four people.
Uzbekistan's Foreign Minister Abdulaziz Kamilov said Akilov was radicalised after moving to Sweden in 2014 and the Central Asian nation's intelligence service had passed on information about him.
“During his stay abroad, he was recruited through the internet by emissaries of the international terrorist organisation the Islamic State,” Kamilov said in quotes from a press briefing published by the ministry.
Kamilov said Akilov had “actively encouraged compatriots to go to Syria to participate in military operations” for the group.
“He repeatedly propagated propaganda videos of terrorist content through internet messengers to his relatives and other connections in Uzbekistan, trying to persuade them to commit violent actions against Uzbek authorities, government officials and law enforcement agencies,” Kamilov said.
“Information about the wrongful acts of Rakhmat Akilov was transferred via the special services to one of our Western partners to further inform the Swedish side,” he added, without giving more details.
A spokeswoman for Sweden's foreign ministry told AFP that it “had not received such information”.
Russian agency Interfax on Wednesday quoted an anonymous security source in Uzbekistan who said a warrant had been issued for Akilov's arrest on extremism charges in February.
Swedish police are currently holding Akilov, whose lawyer says he has already confessed to driving a stolen truck through the crowd and into the front of a department store in central Stockholm.