Bahrain Mirror (AFP): Kuwait's supreme court on Monday upheld the death sentence handed down to the main convict in the Islamic State group bombing of a Shiite mosque that killed 26 people.

The court confirmed the sentence of capital punishment passed on Abdulrahman Sabah Saud, a stateless man who drove the Saudi suicide bomber to the mosque in June last year.

The court also upheld jail terms of between two and 15 years for eight people, including four women, and acquitted 15 others including three women.

The court did not hear the appeals of five others -- four Saudis and a stateless man -- who had been sentenced to death in absentia by a lower court.

Under Kuwaiti law, sentences issued in absentia are not reviewed by higher courts until those convicted appear in person.

The four Saudi men still at large include two brothers who smuggled the explosives belt used in the attack into Kuwait from neighbouring Saudi Arabia. The fifth man is a stateless Arab.

Twenty-nine defendants, including seven women, had been charged with helping the Saudi suicide bomber attack a Shiite mosque in the capital, which was the bloodiest in Kuwait's history.

An IS-affiliated group calling itself Najd Province claimed the bombing as well as suicide attacks on two Shiite mosques in Saudi Arabia in May last year.

Najd is the central region of Saudi Arabia.

The Sunni extremists of IS consider Shiites to be heretics and have repeatedly attacked Shiite targets in the region.

In addition to driving the suicide bomber, Saud was also charged with bringing the explosives belt from a site near the border and aiding the bomber.

At his initial trial, Saud confessed to most charges, but later denied them all in the appeals and supreme courts.

The death penalty in Kuwait is carried out by hanging, and to be implemented it requires the approval of the Gulf state's ruler.

Among the supreme court's main verdicts on Monday, the court upheld the commuting of the death sentence for the alleged IS leader in Kuwait, Fahad Farraj Muhareb, to 15 years in prison.

It also upheld the acquittal of Jarrah Nimer, owner of the car used to transport the bomber.

Courts in Kuwait have previously handed down several verdicts against IS supporters and financiers.