South Korea's president-elect Yoon Suk Yeol holds a news conference in Seoul, South Korea, on Thursday. AP

South Korea’s president-elect Yoon Suk Yeol said Thursday he would solidify an alliance with the United States, build up a powerful military and sternly cope with North Korean provocations, hours after he won the country’s hard-fought election to become its next leader.

Conservative Yoon Suk-Yeol won South Korea's presidential election on Thursday, with the political novice and avowed anti-feminist immediately promising a more hawkish policy on the nuclear-armed North.

READ MORE

US House approves Ukraine aid, Russia oil import ban bill

Turkey hosts top Russia, Ukraine diplomats in bid for peace

After a bitter, hard-fought election campaign Yoon, formerly a top prosecutor who has never held elected office, was declared winner as rival Lee Jae-myung from the incumbent Democratic party conceded defeat.

Some experts say a Yoon government will likely be able to reinforce ties with Washington and improve relations with Tokyo but can’t really avoid frictions with Pyongyang and Beijing.

South Korean President-elect Yoon Suk Yeol (front right) meets his supporters in Seoul, South Korea. AP

The victory of his People Power party looks set to usher in a more muscular foreign policy for the world's tenth largest economy after the dovish approach pursued by outgoing President Moon Jae-in during his five years in office.

Yoon will immediately have to confront an assertive Pyongyang, which has embarked on a record-breaking blitz of weapons tests this year, including a launch just days before the election.

He vowed Thursday to "sternly deal" with the threat posed by Kim Jong Un's regime.

"I’ll rebuild the South Korea-US alliance. I’ll (make) it a strategic comprehensive alliance while sharing key values like a liberal democracy, a market economy and human rights," Yoon told a televised news conference.

"I’ll establish a strong military capacity to deter any provocation completely and protect the people’s safety and property and our territory and sovereignty,” Yoon said. "I’ll firmly deal with illicit, unreasonable behavior by North Korea in a principled manner, though I’ll always leave door for South-North talks open.”