An Indian appeals court Monday confirmed the conviction and death sentence for the only surviving gunman from the 2008 attacks on Mumbai, which killed 166 people and derailed peace talks with neighboring Pakistan.

"The crime is of enormous proportion," Justices Ranjana Desai and R.B. More said while rejecting the appeal by Ajmal Kasab, 22, of Pakistan, who challenged his conviction by a trial court in May. He had been found guilty of murder, waging war against India, conspiracy and terrorism.

Kasab was one of 10 young Pakistanis who attacked two luxury hotels, a Jewish center and a busy train station in India's financial capital in November 2008.

A photograph of Kasab striding through Mumbai's main train station with an assault rifle in hand became the iconic image of the attacks.

"Kasab killed innocent people mercilessly. He displayed extreme perversity and never showed any remorse. He is a threat to the society," the judges said.

Kasab can still challenge the verdict in India's highest court, the Supreme Court, and later apply to the Indian government for clemency.

Such motions often keep convicts on death row for years, even decades. India's last execution — of a man convicted of the rape and murder of a schoolgirl — occurred in 2004.

India blamed the attacks on Pakistan-based militant groups. The attacks escalated tensions between the nuclear-armed rivals and prompted them to suspend peace talks.

Suspicions that Pakistan is not doing enough to bring the perpetrators to justice could hamper ties between India and Pakistan which early this month decided to revive peace talks after a gap of more than two years.