U.S. officials say they have resumed talks with Russian negotiators in Geneva on a new nuclear arms reduction deal.

The long-running talks about a successor to the 1991 Strategic Arms Reduction Treaty were supposed to be finished before it expired on December 5. It limited the number of nuclear warheads and carrier systems each side could deploy.

A spokesman for the U.S. mission in Geneva, Michael Parmly, said on Monday that the 50-member U.S. delegation hopes “the remaining negotiations can be concluded quickly.”

But Mr. Parmly declined to predict when the deal might be concluded.

The Russian Foreign Ministry said last week that it hoped to reach an agreement in “just a few weeks.”

Officials at the Russian mission declined to comment on Monday.