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 microfinance, U.N.-backed health programs, and counternarcotics efforts. She said if Burma continues its reforms, the U.S. would consider upgrading diplomatic relations.

Clinton met with Burmese president Thein Sein, who said the “historic” visit represents a new chapter in relations between the two countries.

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

She is also traveling later Thursday to the main commercial city of Rangoon for talks with pro-democracy leader Aung San Suu Kyi.

Clinton told the Burmese president 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.

Aung San Suu Kyi told a videoconference audience in Washington Wednesday that she definitely plans to run in the next Burmese parliamentary elections. She says her opposition National League for Democracy party will re-register after boycotting the last election in 2010. No date has been set for the new vote.

U.S. State Department spokesman Mark Toner says her intention to run for parliament is a sign that there is an opening in the Burmese political environment. He calls this constructive.

Aung San 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.

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. Mr. Obama has said that if Burma continues to progress, it can forge a new relationship with Washington. But he warned of continued sanctions if the government fails.

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.