South Korea called on North Korea Tuesday to stop provocative remarks and actions, criticizing the communist country for tinkering with a nuclear card. Seoul's call came one day after Pyongyang's deputy ambassador to the United Nations, Ri Tong-il, warned that his country will take additional "nuclear measures," slamming the United States for conducting annual military drills with the South. The envoy said during a news conference that his country "is ready to take a series of additional nuclear measures to demonstrate the power of the self-defensive nuclear deterrent," warning that whether it would take those measures is entirely "up to the U.S.' attitude down the road."    "North Korea should stop making provocative words and actions that flare up tensions on the Korean Peninsula and abide by international obligations including the United Nations' Security Council Resolutions," Seoul's foreign ministry spokesperson Cho Tai-young said during a regular briefing. While stressing that South Korea is watching closely the developments in the North "under close cooperation with the U.S. and countries concerned," Cho declined to predict any chances of the North conducting another round of nuclear test. While Seoul and Washington have said they are defensive in nature, Pyongyang has long denounced the joint Seoul-Washington exercises as a rehearsal for a nuclear war against it, firing a barrage of short-range rockets into waters off its east coast in a show of force.