The Islamic militant who masterminded the Bali bombings was sentenced to death by firing squad after an Indonesian court found him guilty of an "extraordinary crime against humanity."

Imam Samudra waved his fist defiantly and shouted "Allahu Akbar [God is greatest]!" three times after judges sentenced him for the attack on two nightclubs which killed 202 people from 21 countries last October.

Judge Ifa Sudewi said there were no mitigating factors. Samudra, she said, committed "an extraordinary crime and a crime against humanity." Samudra again yelled "Allahu Akbar" as paramilitary police gripped his arms and led him out of court. "Go to hell, kafir [infidels]!" he shouted in Arabic.

Investigators believe Samudra is a leading member of the al-Qaeda-linked Jemaah Islamiyah (JI) terror network, which staged the attack on Western holidaymakers to avenge oppression of Muslims worldwide. He is the second Bali bomber to be sentenced to death – after Amrozi on August 7 – for the worst act of terror since the September 11, 2001 attacks in the United States.

"The defendant is seen as playing a dominant role in the Bali bomb blasts and therefore the judges declare that he is the intellectual actor behind the Bali bomb explosions," Sudewi said. She called the bombings "a cruel, savage, inhuman and from the religious aspect, a forbidden action."

The Afghanistan-trained Samudra, who wore a white Muslim shirt and black cap, has said previously he would welcome death as bringing him closer to God. But Qadhar Faisal, one of his lawyers, told reporters he had instructed them before the verdict to appeal any death sentence. Faisal said Samudra believed the verdict was "haram" (forbidden under Islam) because he should have been tried under Islamic law.

The world's largest Muslim-populated nation, long criticised for ignoring terrorist threats, sprang into action after the Bali bombings killed 164 foreigners – including 88 Australians – and 38 Indonesians. More than 30 Bali suspects are under arrest and most are on trial. They include an alleged senior JI operative called Mukhlas, who is said to have authorised Samudra to go ahead with the attack, and Ali Imron, one of the bombmakers.

Amrozi, Mukhlas and Imron are brothers. Prosecutors are seeking death for Mukhlas and 20 years for Imron. Samudra, 33, attended planning meetings, selected the blast targets in Bali and assigned tasks to the bombers as part of a jihad (holy war) against the United States and its allies. He never admitted links to JI but made no secret of his motives.

"This war is against America and the world understands that America is conceited, arrogant, savage and brutal," he said during the trial. "The war against America and its allies is a war against evil, against tyranny and a war against terrorism and this is jihad in the path of Allah."

Samudra had sought to play down his role in the Bali attack, denying he was the one who picked the targets or gave orders to fellow bombers but admitting involvement in and responsibility for the blasts.

Throughout his trial he displayed a chilling indifference to his victims. He expressed only perfunctory regret at the death of Muslims in Bali, describing it as a "side effect." An unidentified Australian relative of one victim told Elshinta radio he was "very happy" at the outcome. "Tonight when he sits back in his cell he might think about the people that he's actually killed, he might actually finally start to feel some remorse away from the cameras. Who knows?"

Ketut Jontri, whose taxi driver husband was killed in the blast, told AFP she was "very pleased" with the sentence. "One thing that I really want is that when he is executed, I can be allowed to watch – because otherwise I will not believe that he has been executed."