South Korean President Park Geun-hye vowed Friday to "sternly deal with" future provocations by the Democratic People's Republic of Korea (DPRK), warning the northern neighbor against "self-destruction."

"I will sternly deal with any future provocations by North Korea (DPRK)," Park said in a speech to military officers, calling security situations on the Korean peninsula "grave."

"Any country will risk self-destruction if it ignores people's needs and instead focuses on military power," she added. "But if North Korea seeks changes, (South Korea) is ready to make efforts to restore trust."

Park's remarks came after the DPRK said it would sever a military hotline with South Korea and nullify non-aggression agreements between the two countries, a response to newly expanded sanctions approved by the United Nations Security Council.

The toughened sanctions dictate UN member states inspect DPRK ship and air cargo suspected of carrying banned materials and tighten scrutiny of DPRK officials and institutions engaged in illicit activities.

The unanimous decision by the 15-member UN body came after the DPRK's underground nuclear test last month, a follow-up to the controversial December rocket launch largely seen as a disguised missile test.

Earlier in the day, South Korea's defense ministry spokesman Kim Min-seok said the DPRK will "vanish from the earth" if it wages a nuclear attack on South Korea.

South Korea, which expressed support for the fresh sanctions, has stepped up its border surveillance and is ready to " immediately retaliate" if attacked, according to the spokesman.