U.S. Secretary of State Hillary Clinton has called on Burma to end any “illicit” military ties to North Korea, and says more work must be done before the United States can consider lifting sanctions.

Clinton said Thursday during a landmark visit to Burma that its government must respect international consensus against the spread of nuclear weapons in order to improve ties with the United States. She also called for Burma to release more political prisoners and end ethnic violence.

But Clinton also announced several steps to boost relations, including support for micro-finance, U.N.-backed health programs, and counternarcotics efforts.

She met with Burmese President Thein Sein and said if Burma continues its reforms, the U.S. would consider easing sanctions against that country.

Mr. Thein Sein said the “historic” visit represents a new chapter in relations between the two countries.

After her talks with the president, Clinton traveled to the main commercial city of Rangoon for the first of two meetings with pro-democracy leader Aung San Suu Kyi.

Clinton is the first U.S. secretary of state to visit Burma in 50 years.

She told President Thein Sein that she made the trip because both she and U.S. President Barack Obama are encouraged by the steps the Burmese government has taken to help its people.

The new, nominally civilian government took office earlier this year after four decades of military rule.

Clinton also said Thursday that U.S. engagement of Burma should not be seen as a threat to China. Her comments came a day after a state-run Chinese newspaper said China is open to Burma seeking closer ties to the west, but not at the expense of Beijing's interests.

The United States and other Western nations imposed sanctions on the former Burmese military government because of its harsh human rights abuses, including military operations against ethnic groups and the jailing of up to 2,000 political prisoners.

The new Burmese government has released about 200 political prisoners, eased some press restrictions and opened a dialogue with some of its critics, including Aung San Suu Kyi.

Suu Kyi was freed from house arrest last year after spending much of the previous 20 years in detention. Her party won a national election in 1990 by a landslide, but was stopped from taking power.