By Monica Whitlock BBC correspondent in Tashkent

The trial originally began in July, but was adjourned

More than 40 people died in the carnage.

The authorities have accused the 15 of belonging to an Islamic group with links to al-Qaeda.

The trial originally began in July, but was adjourned after suicide bombers staged new attacks outside the US and Israeli embassies in Tashkent.

The suspects sat silently in cages in the courtroom on Tuesday.

Most of them are young men in their early 20s, dressed in tracksuits and flip flops, who gaze at the floor throughout the proceedings.

Two are women kept in a separate cage and wearing the full veil of devout Muslims.

The group could face the death penalty for the charges against them, mainly complicity in a series of killings that shocked the country in late March.

It was the first time that suicide bombers had struck in Uzbekistan.

It seems that the carnage was mainly caused by two young women who blew themselves up at a police drill yard outside a bazaar.

The authorities say the suspects belong to a previously unknown Islamic group called Jamoat, or community.

They say the group has links with international organisations, specifically al-Qaeda.

Significantly, some of the accused have confessed to training in south Waziristan in the Pakistani borderlands close to Afghanistan, where the Pakistani army has been waging a long campaign against militants.

The trial first got going in July, but was adjourned when three more suicide bombers blew themselves up at the US and Israeli embassies, and then at the Interior Ministry.