The United States this month convened a meeting of working-level experts from China, France, Russia and the United Kingdom to discuss nuclear weapons issues, including strategic risk reduction, the US State Department said.

White House national security spokesperson John Kirby said the talks were part of "a routine, continuing dialogue."

The department said on Friday that Washington hosted the meeting on June 13-14 in Cairo among the five nuclear weapons states, describing it as "an ongoing exchange in the context of the Nuclear Non-Proliferation Treaty (NPT)."

The department added the experts were drawn from the countries' respective foreign affairs and defence ministries.

“They "discussed strategic risk reduction, as well as nuclear doctrines and policy," it added.

The NPT, which took effect in 1970, aims to halt the spread of nuclear weapons-making capability and guarantee the right of members to develop nuclear energy for peaceful means.

The treaty allowed the five nuclear weapons states - the permanent members of the United Nations Security Council - to keep their nuclear arsenals.

A state department spokesperson said expert representatives had also met in Dubai in February as part of the dialogue under the NPT, which the United States is currently chairing.

"We found both multilateral conversations to be professional and useful," the spokesperson said in an emailed response that did not address whether bilateral talks took place.

- Reuters