An armored vehicle rolls along a street in downtown Seoul, South Korea, 21 January 2013, as the Capital Defense Command implements a drill under the simulated scenario that armed North Korean agents have infiltrated the capital. Photo by EPA/BGNES
North Korea has threatened South Korea with "strong physical counter-measures" in relation to tougher sanctions imposed earlier this week by the United Nations.
The threat against South Korea came a day after the North said it would carry out a new nuclear test and more long-range rocket launches as part of a new phase of confrontation with the United States.
North Korea threatened on Friday that it would take action against its southern neighbor if it "takes a direct part" in the UN sanctions, CNN has informed.
The UN resolution, passed on Tuesday, expanded existing sanctions against Pyongyang that were imposed after its previous nuclear tests and rocket launches.
North Korea has conducted two nuclear tests in the past, in 2006 and 2009. It gave no time-frame for its third test.