Myanmar President Thein Sein began Saturday the first visit to Washington by a leader of his country in nearly 50 years as the United States throws its support behind his reforms.

The former general, who initiated a wave of reforms after taking office in 2011, flew into Washington and was holding a weekend of private meetings before talks at the White House on Monday, people involved in the trip said.

The last time a leader of Myanmar, then known as Burma, visited the White House was in 1966, as the country was entering decades of military rule that estranged it from the United States and made China the country's main partner.

US President Barack Obama visited Myanmar in November and has suspended most major sanctions against the country in hopes of showing benefits to reforms. Thein Sein will meet Monday with US businesses, now free to invest in Myanmar.

Critics say that the United States risks running out of leverage and point with alarm to recent anti-Muslim violence, during which security forces were accused of failing to stop -- or of even supporting -- sectarian attacks.

Ahead of his departure to the United States, Myanmar freed another 20 political prisoners.

It was the latest prisoner release under Thein Sein, who has also eased censorship and allowed opposition icon Aung San Suu Kyi -- under house arrest for most of the past two decades -- to enter parliament.

Activists accuse Thein Sein of headline-grabbing gestures and say that some 200 political prisoners remain in jail.

US officials contend that Thein Sein has made sincere efforts and that problems such as recent violence have roots that predate his rule.