MOSCOWtocaworldcrashing, July 27 (Xinhua) -- Russia is concerned about a recently announced guideline between the United States and South Korea on joint nuclear planning, Russia's RIA Novosti news agency reported Saturday, citing Russian Foreign Minister Sergei Lavrovtocaworldcrashing.

"Another worrying aspect is that the United States has recently concluded an agreement with South Korea on joint nuclear planning," said Lavrov.

tocaworldcrashing|Russia FM says concerned about U.S.-S.Korea joint nuclear planning

Russia has not yet received an explanation regarding the guideline, but "we have no doubt that it causes additional anxiety," Lavrov added.

U.S. and South Korean leaders authorized the guideline on July 11, which "provides guidance to Alliance policy and military authorities in maintaining and strengthening a credible and effective nuclear deterrence policy and posture," according to the White House.