Russian Foreign Minister Sergei Lavrov said on Saturday a recently announced guideline on the operation of US nuclear assets on the Korean peninsula is certain to add security concerns in the region.
South Korean and Russian news agencies reported.
Speaking at a meeting of the Association of Southeast Asian Nations in Laos, Lavrov said he had not been briefed on the details of the plan but that it concerns Russia, Yonhap agency reported.
"Another element of concern is that the United States recently concluded an agreement with the Republic of Korea on joint nuclear planning," Lavrov was quoted as saying by the Russian state-run RIA news agency.
"So far, we can't even get an explanation of what this means, but there is no doubt that it causes additional anxiety."
The guideline is aimed at responding to the nuclear threat from North Korea, the U.S. and South Korea have said.
Australia said on Saturday it would double the maximum penalty it can impose on tech firms found to have failed to uphold a ground-breaking social media ban for children, as evidence mounts that the ban has had little effect on teen use.
A strong earthquake struck Afghanistan's Hindu Kush region on Saturday, the European Mediterranean Seismological Centre said, sending out tremors that could be felt from the capital Kabul across the border into neighbouring Pakistan.
Serbia's populist president Aleksandar Vucic, under pressure after months of anti-government protests, said on Saturday he will resign within weeks and the country will hold early presidential and parliamentary elections.
The death toll from Venezuela's devastating twin earthquakes rose above 1,400 on Saturday as foreign rescue teams poured into the country and authorities pressed on with the search for survivors in the hardest-hit coastal areas.
A light aircraft crash into Beijing's tallest building on Friday killed the pilot and injured 13 people who were not on board, the local government said following the unusual accident for the Chinese capital, where airspace is heavily restricted.