LeT, considered the best-funded terror outfit in the region, had carried out the audacious 2008 Mumbai terror attacks which killed 166 people, including Americans and other foreigners.
Blaming LeT for carrying out attacks on US forces in Afghanistan, Admiral Robert Willard, Chief of the US forces in the Pacific, told lawmakers that America had evidence of the group's presence in Europe, the broader Asia Pacific and even in the past in Canada and here, CNN reported.
LeT was cultivated by Pakistan's security establishment two decades ago to wage a guerrilla war to wear down Indian security forces in Kashmir, the US media report said.
At a Senate hearing, Admiral Willard said "the discussion regarding the government of Pakistan's relationship to LeT is a very sensitive one."
His comments come at a time when US is sharply focussing on the group particularly since the arrest of Pakistani American David Headley in 2009.
According to Headley's statement to US authorities, he had joined LeT to fight in Kashmir but ended up scouting targets for the Mumbai attackers.
Last week, the White House in a report to Congress warned that despite unprecedented efforts by Pakistan to go after the militants within the country, it lacked "a clear path" to defeat them.
Admiral Willard told the lawmakers that the US was working actively with South Asian governments including India, Nepal, Bangladesh, to help build their capacities to contain LeT.