The United States said Tuesday it wanted an immediate meeting with Russia to finalize an extension of a nuclear treaty after Moscow backed a US proposal to freeze warheads. "We appreciate the Russian Federation's willingness to make progress on the issue of nuclear arms control," State Department spokeswoman Morgan Ortagus said. "The United States is prepared to meet immediately to finalize a verifiable agreement. We expect Russia to empower its diplomats to do the same." sct/dw