President Joe Biden said Friday that more than 30 countries have joined the United States in tapping national oil reserves in an attempt to settle global energy markets spooked by fallout from Russia's military operation in Ukraine.

"This morning, over 30 countries from across the world convened in an extraordinary meeting and agreed to the release of tens of millions of additional barrels of oil onto the market," Biden said in an address from the White House.

On Thursday Biden ordered a major release of oil from America's reserves in an effort to bring down high fuel costs. The release of up to 180m barrels of oil over six months is the largest since the reserve was created in 1974.

But the release - of about 1m barrels a day - is unlikely to fully resolve the energy crisis, analysts say.

He promised further action to boost U.S. output, saying the release would "serve as [a] bridge until the end of the year when domestic production ramps up".

(With input from agencies)