Myanmar's President Thein Sein will visit Thailand for three days later this month, a trip that he has twice postponed.

His arrives July 22, a government official said.

Thein postponed the visit two times, the last time for the beginning of June.

He was believed dissatisfied with the massive publicity surrounding Myanmar's opposition leader Aung San Suu Kyi during her own trip to Thailand at the time, a report by Mizzima news Web site said.

Suu Kyi's six-day visit was her first trip outside Myanmar in more than 20 years for fear the former ruling junta wouldn't have allowed her back in.

Suu Kyi was in Thailand to address the World Economic Forum but also spoke out about the pace of change and speed of establishing democracy in Myanmar, formerly called Burma.

She warned that the roots of change are still new and could falter.

Her remarks elicited a terse response from an adviser to Thein, a former junta leader and now an elected member of Parliament.

"Personally, I really admire her, but I have a doubt," the adviser, U Nay Zin Latt, said via e-mail, a report by The Times report said, noting that public criticism of Suu Kyi is rare.

Suu Kyi and Thein Sein have been striving to improve their relationship since the military handed over power after elections in November 2010 to a nominally civilian government -- one-quarter of legislative seats are reserved for military appointees.

Suu Kyi, now a member of Myanmar's Parliament, won a national election 20 years ago but was refused power by the ruling military government.

She spent most the next 20 years under some form of detention and wasn't allowed to participate in the 2010 national election. However, she won a seat in April by-elections.

Critics of Myanmar's government of former senior military officers have said it remains rule by the military in all but name.

But the government's moves toward a more open society have been welcomed widely by many countries in the West.

Thein also has made attempts to improve diplomatic ties with its Asian neighbors as it continues to struggle to rein in ethnic rebels in several frontier states, including areas adjoining Thailand.

The fighting has created refugee problems, with thousands of Myanmar groups fleeing across borders.

During Suu Kyi's trip to Thailand in June she visited the Mae La camp on the border with Myanmar.

Mae Le is one of the largest in Thailand for ethnic Karen people escaping the fighting in Myanmar's Karen state.

"I won't forget you. I'll try my best for you," Suu Kyi told cheering crowds in the camp.

Ahead of Thein's visit to Thailand, the government announced it would release around 80 Thai citizens detained in prison in Kawthaung, southern Myanmar.

They were arrested last week for crossing into Myanmar and allegedly carrying out illegal logging.

Security forces seized timber-cutting machinery, bulldozers, guns and trucks, a report by the Myanmar news Web site Irrawaddy said.

The military also was looking for other Thais that might be hiding in the thick forests, a police officer told Irrawaddy.

Despite the incursion, there appears no tension between Thai and Myanmar security forces at the Ranong-Kawthaung border area over the incident, a local source told The Irrawaddy.

Myanmar's relations with the United States also continue to improve.

Last week the government formally accepted the appointment of Derek J. Mitchell as the first U.S. ambassador to Myanmar in 22 years, a report by the Myanmar government's official newspaper New Light of Myanmar said.

The U.S. Senate confirmed Mitchell's appointment at the end of last month.

Mitchell, a veteran U.S. policymaker on Asia-Pacific affairs, has been President Barack Obama's special envoy to Myanmar since August.

Mitchell holds a bachelor of arts degree from University of Virginia in 1986 and obtained a Master of Arts degree in Law and Diplomacy from the Fletcher School of Law and Diplomacy, Tufts University in 1991.

From 2001-2009 he served as Asia Director at the International Security Program, Center for Strategic and International Studies, Washington, D.C.

He also served as principal deputy assistant secretary of defense, Asian and Pacific Security Affairs, U.S. Department of Defense from 2009-2011.