BALI, Indonesia (AP) _ An Indonesian court convicted and sentenced to death Thursday an Islamic militant for his role in the Bali bombings, delivering the first verdict for the attack that killed 202 people.

After the ruling was read, a defiant Amrozi bin Nurhasyim smiled, raised his arms and gave his lawyers the thumbs-up sign. Hundreds of people, including survivors of the bombings, cheered when the judge read the harsh sentence.

Amrozi was found guilty of planning and helping execute the bombings _ a verdict that could help end Indonesia's reputation as being soft on terrorists. About three dozen other suspects are to be tried for the bombings.

``The accused is found guilty in a legal and convincing manner of carrying out an act of terrorism,'' Judge I Made Karna said.

The verdict came two days after a bomb exploded at the Marriott Hotel in Jakarta, killing at least 10 people and wounding nearly 150.

The Marriott blast was a bloody reminder of the threat of terror in the world's most populous Muslim nation, which had won plaudits for its investigation into the Bali bombings.

Both attacks have been linked with Jemaah Islamiyah, a shadowy al-Qaida-linked terrorist group believed to be operating in Southeast Asia.

Amrozi, a 41-year-old mechanic from the island of Java, has been called the ``smiling bomber'' because of his jocular manner and lack of remorse after his arrest last year. During a peer's trial, he grinned and yelled out ``Bomb!'' when asked about Tuesday's explosion in Jakarta.

As he was led out of the courtroom Thursday, Amrozi smiled broadly at Australian survivors, some of whom shouted back angrily. Australia lost 88 people in the attack.

Natalie Yuniardi, an Indonesian whose Australian husband died in the blast, came to court with her baby on her arms. She wept after the verdict was read.

``I will only be happy when all of them are put to death,'' she said.

Indonesia's government has been eager to show the world that it is committed to bringing the perpetrators to justice.

``The Balinese people will be rejoicing today,'' said Julia Ika Setiani, a university student who attended the trial. ``My family and my friends have suffered because of this grisly bombing.''

If the Amrozi verdict is followed by similar convictions for other alleged bombers, Indonesia's notoriously inefficient judicial system could get a much needed boost in its efforts to confront Islamic extremism.

Amrozi's was the first of at least three dozen cases to come to trial for the bombing. Prosecutors said that while Amrozi did not participate in the actual attack, he purchased a van and explosives used in the car bomb that flattened Bali's crowded Sari Club and nearby Paddy's Bar.

Although Indonesian law allows for death sentences to be handed down for crimes such as murder and terrorism, in practice executions are rare.

Amrozi's attorney, Wirawan Adnan, said they will appeal the sentence ``not because we believe he is innocent, but because he was mistreated and was not been given a fair trial. We do not believe that he deserves the death penalty, he was not the mastermind.''

Most of Bali's 3 million people are Hindu, unlike the rest of Indonesia's 207 million people who are predominantly Muslim. Several of the alleged bombers said they picked the venue to kill as many Westerners as possible to avenge the treatment of fellow Muslims in other parts of the world.

Prosecutors allege the Bali strike was part of a campaign by Jemaah Islamiyah to set up a fundamentalist Islamic state in Southeast Asia.

Maj. Gen. Made Pastika, who led the Bali investigation, said Thursday that in the Bali and Marriott cases attackers used mobile phones to detonate car bombs. Also like the perpetrators of the Bali bombers, the Marriott attackers used both TNT and RDX explosives, he said.

In Jakarta, Brig. Gen. Dudon, the chief forensics specialist, said vital clues in the Marriott attack may have been washed away when firefighters used water to put out the blaze.

Dudon said it was still not possible to determine whether the attack had been carried out by a suicide bomber. Several Indonesian officials had earlier said it may have been.

Investigators said they were using video evidence taken from the hotel's security cameras to see if they could help identify the driver of the vehicle. Police released a composite sketch of a man who may have been behind the wheel.

On Thursday, police said they had arrested two people over three recent bombings in the capital, but the pair are not suspected in the Marriott blast.

Police Col. Andi Chairuddin said the two men were arrested late Wednesday in two separate locations in eastern Jakarta.

The two were allegedly involved in a bombing at Jakarta's International Airport on April 28 that injured 11 people, and two other smaller blasts at parliament and near the United Nations building in Jakarta, Chairuddin said.