U.N. Secretary-General Ban Ki-moon says he plans to visit Myanmar this weekend because there is "an unprecedented opportunity" to help promote its transition to democracy at this "critical moment."

Ban announced the trip after meeting Monday with the Group of Friends of Myanmar, which includes Western nations pushing for human rights reforms and the country's Asian trading partners.

He told reporters he accepted an invitation from President Thein Sein and would explore practical ways the U.N. can help the country.

The U.N. chief said Myanmar has seen encouraging economic and political reforms followed by recent landmark elections and important steps towards reconciliation, but he said the country's transition is also fragile and many challenges lie ahead.