Uzbekistan said on Friday it had warned the West about terror suspect Rakhmat Akilov, who has confessed to launching a truck attack in the Swedish capital on April 7 that killed four people.

Foreign Minister Abdulaziz Kamilov said its security services had informed a Western ally that Akilov had ties to "Islamic State" (IS) jihadists, Russian media reported. He did not identify the country or intelligence organization concerned.

Kamilov said the 39-year-old Uzbek national had been radicalized after he moved to Sweden in 2014.

 Links to IS in Syria

"During his stay abroad, he [Akilov] was recruited through the internet by emissaries of the international terrorist organization the Islamic State," Kamilov said at a press briefing in Tashkent, the Russian state news agency RIA Novosti reported.

"According to the information that we have, he actively urged his compatriots to travel to Syria in order to fight at Islamic State's side," Kamilov added.

Akilov was arrested hours after he is alleged to have plowed a hijacked truck into shoppers on a busy Stockholm street. As well as the four deaths, fifteen people were injured in the attack, outside a department store.

Sweden: 'Not a serious threat'

A spokesman for Sweden's security police declined to comment on the statement from Uzbekistan.

Swedish police said last week they had intelligence on Akilov in 2016 that they could not verify and they had not viewed him as a serious militant threat.

Earlier this week, an Uzbek security source said Akilov had been detained at the Turkish-Syrian border in 2015 and deported back to Sweden.

An anonymous security source in Uzbekistan was cited by Russia's Interfax news agency as saying that an arrest warrant had been issued for Akilov on extremism charges in February.

Since the attack, Sweden's center-left government has said it will fast-track plans to make it a criminal offense to be a member of what it deems a terrorist group.

Norway introduced a similar anti-terror law in 2013.