WASHINGTON (AFP) - The United States must press Myanmar to reveal the state of its nuclear programme and any ties with North Korea as a condition for better relations, a key US lawmaker urged Monday. "An early goal of the tentative US re-engagement with Burma should be full disclosure of the extent and intent of the developing Burmese nuclear program," said top Senate Foreign Relations Committee Republican Richard Lugar. Lugar's comment came as US Secretary of State Hillary Clinton prepared to become the most senior US official in 50 years to visit Myanmar.