A senior U.S. official said Russia has procured more than 16-thousand-500 containers of munitions and related supplies from North Korea since North Korean leader Kim Jong-un visited Russia in September last year.

Robert Koepcke, deputy assistant secretary of state for South Korea, Japan and Mongolia, made the remarks Wednesday during a security forum in Washington, saying Russia has launched 65 North Korean missiles at Ukraine. 

If Pyongyang refuses dialogue and continues its provocations, Koepcke said, the United States will have no choice but to take steps to protect itself and its allies.

But he added that the door is still open, saying Washington remains committed to diplomacy and will engage in dialogue with the North with no preconditions.

He added that in addition to security issues, humanitarian issues such as human rights and reunions of separated families may be part of the agenda in any future dialogue. 

The remarks came amid concerns that North Korea may engage in provocations around the time of the U.S. presidential election in November, such as a nuclear test.