MOSCOW — U.S. Secretary of State Mike Pompeo and Russian Foreign Minister Sergey Lavrov discussed arms control and other issues Friday as Moscow has signaled readiness to include some of its latest nuclear weapons in the last remaining arms control pact between the two countries. But first Washington must accept the Kremlin’s offer to extend the agreement.

The State Department said the two top diplomats discussed next steps in the bilateral strategic security dialogue. Pompeo emphasized that any future arms control talks must be based on U.S. President Donald Trump’s vision for a trilateral arms control agreement that includes China along with the U.S. and Russia, the State Department said.

Russian President Vladimir Putin has offered to extend the New START arms control treaty that expires in 2021. The Trump administration has pushed for a new pact that would include China as a signatory. Moscow has described that goal as unrealistic given Beijing's reluctance to discuss any deal that would reduce its much smaller nuclear arsenal.

Deputy Foreign Minister Sergei Ryabkov said Friday that Russia’s new Sarmat heavy intercontinental ballistic missile and the Avangard hypersonic glide vehicle could be counted along with other Russian nuclear weapons under the treaty.

The Sarmat is still under development, while the first missile unit armed with the Avangard became operational in December.

The New START Treaty, signed in 2010 by U.S. President Barack Obama and Russian President Dmitry Medvedev, limits each country to no more than 1,550 deployed nuclear warheads and 700 deployed missiles and bombers.

The treaty, which can be extended by another five years, envisages a comprehensive verification mechanism to check compliance, including on-site inspections of each side’s nuclear bases.

New START is the only U.S.-Russia arms control pact still in effect. Arms control experts have warned that its demise could trigger a new arms race and upset strategic stability.