Pakistani authorities say they have arrested the radical Islamist leader accused of masterminding the 2008 attacks in Mumbai that killed 166 people.
Hafiz Saeed's arrest on July 17 came one day before Prime Minister Imran Khan was set to hold meetings with U.S. officials in Washington, D.C. Khan has pledged to crack down on militant groups.
U.S. President Donald Trump, who has criticized Islamabad for what he says is an insufficient effort to crack down on terrorism, hailed the arrest of the suspected mastermind.
"After a ten-year search, the so-called 'mastermind' of the Mumbai Terror attacks has been arrested in Pakistan. Great pressure has been exerted over the last two years to find him!" Trump wrote on Twitter.
After Trump's remarks, the House Foreign Affairs Committee tweeted that "Pakistan wasn't searching for him for 10 years" and Saeed had been "living freely," and had been arrested and released eight times since 2001.
Shahbaz Gill, a spokesman for the governor of Punjab Province, said Saeed was arrested near the central Pakistani town of Gujranwala and charged with "gathering funds for banned outfits."
U.S. and Indian officials have accused Saeed of helping plan the Mumbai attacks in which 10 gunmen rampaged through India's largest city, shooting up two luxury hotels, a Jewish center, and a train station during a siege that lasted several days.
India accused Pakistan of helping organize the attacks in cooperation with Saeed, who is head of the Jamaat-ud Dawa charity. U.S. officials say the group is a front for the banned Pakistan-based militant group Lashkar-e Taiba.
Pakistan and Jamaat-ud Dawa have denied involvement in the Mumbai attack.
The United States has designated Saeed a terrorist and offered $10 million for information leading to his arrest and conviction.
The United States has long accused Pakistan of providing "havens" for militant groups fighting in India and Afghanistan, and Trump has cut financial and military aid to Islamabad.
After the arrest, Alice Wells, the U.S. acting assistant secretary of state for South Asia, wrote on Twitter that a "full and expeditious prosecution for his involvement in numerous acts of terror, such as the Mumbai attacks that killed 166 people, including six Americans, is necessary."
"The victims of terrorist attacks deserve justice," she added.
The United States has long accused Pakistan of harboring militant groups fighting in India and Afghanistan.
U.S. President Donald Trump has accused Pakistan of providing "safe havens" for the Taliban and cut financial and military aid to Islamabad.
Khan will be accompanied to Washington by Pakistani Army chief General Qamar Javed Bajwa and Lieutenant General Faiz Hameed, the head of Inter-Services Intelligence (ISI), the military's spy wing.
The all-powerful army has an oversized role in the domestic and foreign affairs of the South Asian country, and has long been accused of using the Afghan Taliban and other militant groups as proxies in neighboring Afghanistan and India.