A key U.S. senator and backer of Burma's democracy movement says he is impressed with reforms initiated by the country's new, nominally civilian government, but says more needs to be done.

Mitch McConnell, the Senate Republican minority leader, spoke Monday, after meeting for more than an hour in Rangoon with pro-democracy leader Aung San Suu Kyi.

“''The United States has been very impressed with the changes that are occurring. I am also convinced based on our conversations with Aung San Suu Kyi that these are real changes and the country is heading in the right direction.''

McConnell is the latest in a string of prominent Westerners to visit Burma, which was subjected to decades of military rule until the junta relinquished power and permitted elections last year. Monday, McConnell said he looked forward to Burmese by-elections later this year as a key condition for lifting U.S. economic sanctions.

''We also look forward to a free and fair election, a by-election on April 1st, and in the wake of that, I think it would be appropriate for us to further consider in the United States, the various sanctions that we have in place and the appropriateness of continuing those.''

Burmese President Thein Sein last week ordered the release of hundreds of prisoners, many of them democracy advocates jailed by the former junta.

U.S. President Barack Obama called the prisoner release “a substantial step forward for democratic reform.”

For his part, United Nations Secretary-General Ban Ki-moon described Friday's prisoner release as the most significant to date because it included a number of key, prominent political figures able to contribute to national reconciliation.

Burmese state media said the detainees were freed under an amnesty ordered by President Thein Sein to foster national reconciliation.