A senior US official on Tuesday paid homage to the victims of the January 22, 2002, attack on the American Center in Calcutta that left five policemen dead and a city stunned.

Gentry Smith, the assistant secretary of state for diplomatic security, was at the American Centerfor a wreath-laying ceremony.

“I want to make it understood how much we appreciate the sacrifices and contributions and the services they have made for keeping this facility safe... and also to recognise the families who lost their members. The police and law-enforcement persons continue to do their job on a daily basis,” said Smith, who oversees the law enforcement and security arm of the US department of state and is touring India now.

“It is a calling to service to make sure that those who we are brought to protect are safe, sometimes that even calls for paying the highest cost. It is onlyappropriate that wehonour those who do pay that cost.”

The attack took place at 6.30am on January 22, 2002, when the security personnel were changing shifts. Motorcycle-borne assailants fired at the guards, killing five and injuring 20 people.

Hours after the attack, a man introducing himself as the Dubai don Aftab Ansari had called The Telegraph office to claim responsibility for the attack. He said the cops had been killed to avenge the death of his friend Asif in an encounter in Gujarat.

Ansari was detained in the United Arab Emirates (UAE) when he was about to board a flight to Islamabad from Dubai on January 23, a day after the attack, and deported to Delhi.

The police had filed a case against nine persons in the case.

Ansari and another convict, Jamiluddin Nasir, were awarded death by the trial court on April 26, 2005. The sentences were confirmed by Calcutta High Court on February 5, 2010.

On May 21, 2014, the Supreme Court commuted the death penalty to life term.

On May 21, 2009, Ansari was sentenced to life imprisonment for conspiring to abduct footwear baron Partha Pratim Roy Burman for ransom in 2001.

Ansari is now lodged at Presidency jail, said a police officer. In his mid-50s, the once-dreaded don now suffers from multiple ailments, including diabetes. “He reads newspapers regularly,” a source in the jail said.

On Tuesday morning, Kathy Giles-Diaz, the US consul-general in Calcutta, and senior police officers joined Smith in paying floral tributes at a memorial dedicated to the five cops who died in the attack — Asraf Ali, Ujjal Barman, Suresh Chandra Hembram, Anup Kumar Mondal and Pijush Kanti Sarkar.

The 2002 raid is the only attack on any American diplomatic institution in India, said Giles-Diaz.

“The attack was not just on a building but on the shared values, the connection and collaboration between the US and India. Today, we honour not only the people who lost their lives but the bond that unites us,” she said.