The Uzbek immigrant behind New York's worst attack in 16 years confessed to acting in the name of the Islamic State group and "felt good" about the killings, having planned an assault for a year, investigators said Wednesday.

A 39-year-old Uzbek national suspected of mowing down a crowd of people on a busy Stockholm street in a stolen truck on Tuesday admitted committing "a terrorist crime," his lawyer said.

Uzbekistan's interim leader Shavkat Mirziyoyev has won a landslide victory to become the country's second-ever president following the death of long-reigning strongman Islam Karimov, official results said Monday.

Uzbekistan awaited Monday the results of a vote to elect a successor to late strongman Islam Karimov, with long-serving premier Shavkat Mirziyoyev seen scoring a comfortable victory against weak opponents.

Uzbekistan's President Islam Karimov died Friday, the government announced, ending over a quarter of a century of his iron-fisted rule in the Central Asian nation with no clear successor lined up.

Strongman Uzbek President Islam Karimov is in intensive care after suffering a brain haemorrhage, his younger daughter wrote on social media on Monday.

The ministry's announcement, which the company also confirmed Friday, said the state-owned Center of Radio Communication, Broadcasting and Television had become "sole owner" of the pair's joint venture after MTS sold off its 50.01 percent stake.