South Korean President-elect Park Geun-hye vowed Thursday to make national security a priority as she warned about the dangers posed by North Korea.

In her first major speech since being elected Wednesday, Ms. Park said Pyongyang's recent rocket launch demonstrates the seriousness of the threat facing her country. She also hinted at greater engagement with the North.

“I will keep my promise to the people, that I will open the Korean peninsula's new era through strong security and diplomacy, based on trust.”

The conservative lawmaker, who on Wednesday became the first woman ever to win a presidential election in South Korea, has said she will seek to improve ties with Pyongyang, but is reluctant to do so until it makes concessions on its nuclear program.

Ms. Park, who is the daughter of the late military ruler Park Chung-hee, won 51. 6 percent of the vote, compared to 48 percent for her rival Moon Jae-in.

Prior to her Thursday speech, Park visited the graves of her father and mother, both of whom were assassinated.

U.S. President Barack Obama congratulated Ms. Park Wednesday and said he is looking forward to working closely with her administration on issues of mutual concern.

United Nations chief Ban Ki-moon, South Korea's former foreign minister, issued a statement expressing hope for “even more active engagement” by South Korea in U.N. efforts to promote sustainable development, global peace and human rights, and fight against climate change.

Ms. Park's father, who ruled the country for 18 years, is both admired for dragging the country out of poverty and reviled for his suppression of dissent. He was assassinated in 1979.

Despite frigid cold, voter turnout in this election was high. It was measured at close to 76 percent, surpassing the turnout of the previous two presidential elections.