US Secretary of State Hillary Clinton is in Moscow for talks on the Middle East and to seek a preliminary agreement with Russia on a nuclear arms reduction pact.
US officials say they have made good progress over the past week.
Russian and US negotiators have been meeting regularly in Geneva for more than six months to work on the new document.
When Clinton met her Russian counterpart there a year ago, there was a slight hiccup in the formalities. She presented Sergei Lavrov with a “reset” button to symbolise improved relations.
But the word “reset” was mistranslated into the Russian for “overcharge”.
A year on, the business is more serious. The two countries are trying to replace the 1991 START agreement. The main sticking point is the US plan for an anti-missile defence system in eastern Europe, which Russia opposes.
The US says it has more than 2,000 nuclear weapons; Russia is thought to have nearly 3,000.
US optimistic over Russian nuclear talks