(CNN) -- A key member of the U.S. Senate Foreign Relations Committee announced Thursday that he has postponed an upcoming trip to Myanmar out of concern that Myanmar's government is working with North Korea on the development of a nuclear program.
Sen. Jim Webb, D-Virginia, noted that, according to initial news accounts, "a defecting officer from [Myanmar's] military claims direct knowledge of such plans, and reportedly has furnished documents to corroborate his claims."
Webb said it is unclear "whether these allegations have substantive merit." However, in light of the U.S. State Department's recent accusation that Myanmar -- also known as Burma -- has violated a U.N. Security Council resolution "with respect to a suspected shipment of arms from North Korea, there are now two unresolved matters related to activities of serious concern between these two countries."
Webb said, "Until there is further clarification on these matters I believe it would be unwise and potentially counterproductive for me" to visit Myanmar.
Webb urged President Barack Obama to appoint a special envoy to address "the entire range of issues" affecting relations between the United States and Myanmar.
In August 2009, Webb became the first American official to meet with Myanmar's junta leader, Senior Gen. Than Shwe, when the senator went to Myanmar to secure the release of American John Yettaw. Yettaw was sentenced to seven years of hard labor after swimming to the home of pro-democracy leader Aung San Suu Kyi in Yangon, where she has been under house arrest for 14 of the past 20 years.
Webb, who chairs the East Asia and Pacific affairs subcommittee of the Senate Foreign Relations Committee, also met with Suu Kyi during that trip.
A military junta has ruled Myanmar since 1962.