Media reported earlier Tuesday that communist North Korea was on the verge of conducting nuclear tests.
"We believe that this move could lead to a further escalation of the military-political situation on the Korean peninsula and around it and could affect the international nuclear non-proliferation system," the ministry said in a statement.
In early July, North Korea, which claims to have nuclear weapons, conducted test launches of ballistic missiles, including a long-range Taepodong-2. Many countries interpreted the tests as an attempt to force the international community, especially the United States, to make concessions over the six-nation nuclear talks.
The talks, which involve North and South Korea, Russia, China, Japan and the U.S. opened in 2003, but stalled last November.