MUMBAI (Reuters) - India on Monday paid tribute to the more than 160 people killed in a 2008 Islamist militant attack on the city of Mumbai, the 10th anniversary of an assault that raised fears of war with Pakistan.

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Senior state politicians laid wreathes and paid tribute to the victims at a Martyrs’ Memorial in downtown Mumbai, while other events were held at some of the sites of the three-day attack, which began on Nov. 26, 2008.

Six Americans were among the 166 people killed by 10 gunmen who infiltrated the financial hub by boat and spent three days spraying bullets and throwing grenades around various city landmarks. [reut.rs/2DIQvAM]

“A grateful nation bows to our brave police and security forces who valiantly fought the terrorists during the Mumbai attacks,” Prime Minister Narendra Modi said on Twitter.

India has blamed militants linked to the Pakistan-based Lashkar-e-Taiba (LeT) group for the attacks and said the gunmen, all but one of whom were killed in the assault, were Pakistani.

Pakistan condemned the attack, denied involvement of any of its agencies and offered to cooperate with India in the investigation.

Nevertheless, tension soared between the nuclear-armed rivals after the attacks.

India and the United States accused Hafiz Saeed, who founded the LeT, of being the attack mastermind. He denied involvement but Pakistani authorities placed him under house arrest for different periods. He was most recently released in November 2017.

U.S. Secretary of State Michael Pompeo called on Pakistan to uphold their U.N. Security Council obligations to implement sanctions against those responsible for this attack, including LeT and its affiliates.

“It is an affront to the families of the victims that, after ten years, those who planned the Mumbai attack have still not been convicted for their involvement,” Pompeo said in a statement.

A spokesman for the Pakistan government did not immediately respond to a request for comment.

The U.S. State Department also announced a reward of up to $5 million for any information leading to arrests or convictions of those involved in the execution of the 2008 Mumbai attack.

Mumbai’s Chabad House, a Jewish center the gunmen attacked, unveiled a memorial to the victims on Sunday, renaming the center the “Nariman Light House”.

India secretly hanged the lone survivor of the militant squad, Pakistan national Mohammad Ajmal Kasab, in 2012.