The United States said it was ready to deploy air and naval assets - including two ships - to help secure the Winter Olympics in Russia after terror threats.
The offer came after US concern about possible attacks at the event, which starts in the Black Sea city of Sochi on February 7.
"The US has offered its full support to the Russian government as it conducts security preparations," Rear Admiral John Kirby said on Monday.
"Air and naval assets, to include two navy ships in the Black Sea, will be available if requested for all manner of contingencies in support of - and in consultation with - the Russian government."
US Defence Secretary Chuck Hagel had already offered American support during a January 4 phone call with his Russian counterpart Sergei Shoigu.
Islamist insurgents based in North Caucasus republics such as Dagestan, who are seeking their own independent state, have vowed to disrupt the Sochi Games to undermine Russian President Vladimir Putin.
In a new video threat posted on a prominent North Caucasus Islamist website, two men sitting in front of a jihadist flag warn of planned attacks at the event.
US lawmakers have said Russia was not adequately sharing intelligence with Washington.