The US has called for other permanent members of the United Nations Security Council to adhere to the Nuclear Non-Proliferation Treaty.
The call Thursday by Undersecretary of State for Arms Control and International Security Affairs Andrea Thompson in Beijing comes as the U.S. is preparing to withdraw from a separate pact, the 1987 Intermediate-Range Nuclear Forces Treaty between the United States and the former Soviet Union.
Thompson says some countries are violating non-proliferation and developing new weapons programs, a likely reference to Russia, Iran and possibly North Korea. The NPT aims to stop the spread of nuclear weapons.
The 1987 treaty bans production, testing and deployment of land-based cruise and ballistic missiles with a range of 500-5,500 kilometers (310-3,400 miles).
NATO secretary-general has urged Russia to respect the 1987 treaty.