The United States has pushed for a broadening of the main agreement to control nuclear arms with Russia as it pushes for China to join the talks.
Speaking after talks in Vienna on June 23, U.S. Special Presidential Envoy for Arms Control Marshall Billingslea told a news conference that he and Russian Deputy Foreign Minister Sergei Ryabkov had made enough progress that they agreed to set up "multiple" technical working groups, with a second meeting depending on their progress as they look to replace the 2010 New Strategic Arms Treaty (New START) before it expires in February.
"We, the United States, intend and believe...that the next arms control agreement must cover all nuclear weapons, not just so-called strategic nuclear weapons," Billingslea said.
The last remaining nuclear arms control agreement, the New START treaty caps the number of deployed long-range nuclear warheads each can have.
Ryabkov called the agreement to continue negotiations "a significant step forward."
Russia has called for an extension of the accord limiting Russian and U.S. nuclear arsenals to 1,550 deployed long-range nuclear warheads each.
However, Washington has said that its bilateral arms control agreements with Moscow are outdated. Moreover, it wants China to be included in any future agreements on nuclear weapons even though Beijing has repeatedly rejected attempts to get it to join the talks. While the country has been expanding its nuclear arsenal, it is still far smaller than the U.S. and Russian programs.
Ryabkov told Interfax that while Russia considers that arms control talks should be multilateral, "we cannot 'force' or 'persuade' anyone to join such talks," adding that the U.S. insistence on including China was "unrealistic."
U.S. President Donald Trump has pulled out of or let expire a number of international agreements, including the Intermediate-Range Nuclear Forces Treaty and the Iran nuclear deal. But his administration has voiced a general interest in preserving New START.
Russia, whose nuclear arsenal is a key element of power and is vastly outspent on defense by the United States, says it wants to ensure parity with Washington.
It also wants a broader discussion with Washington on arms control, including on U.S. threats to resume nuclear tests after a suspension of nearly three decades.
Last month, Billingslea accused Moscow of modernizing thousands of "nonstrategic" nuclear weapons that fall outside of the New START treaty.
"They have adopted a highly provocative nuclear doctrine that embraces early escalation and use of nuclear weapons," he said, calling for any successor treaty to put more Russian arms under monitoring.