North Korea nuclear warheads
South Korean (blue headbands) and U.S. Marines take positions as amphibious assault vehicles of the South Korean Marine Corps fire smoke bombs during a joint landing operation drill in Pohang, South Korea Kim Hong-Ji/Reuters

The United States President-elect Donald Trump has reaffirmed South Korean President Park Geun-hye during a phone call on Thursday (10 November) that he is committed to defend South Korea under an existing security alliance, an official told Yonhap news agency.

Trump said that the US will maintain a "strong, firm" defence posture to defend its Asian ally, during the phone call that lasted for 10 minutes.

The assurance comes after President Park congratulated Trump for his victory and insisted that Washington and Seoul built an alliance based on trust and faced a series of challenges together over the last six decades. She also said that the friendship between both countries has served as "cornerstone" of peace and prosperity in Asia Pacific.

"I expect that (we) can strengthen and develop the alliance down the road for the shared interests in various areas," she said during the call to which Trump responded by saying that he completely agreed with her.

She also raised North Korea's nuclear issue and said that it was the "greatest threat" facing the two countries. "Given that in the past, North Korea staged provocations during the period of the government transition in the U.S., we need to closely cooperate in advance to thoroughly deter possible North Korean provocations and respond sternly if provoked."

According to the official, Trump also said that the US will work with South Korea "until the end" for the security of both countries.

Meanwhile, South Korea's military held a meeting on Thursday to evaluate the potential impact of Trump's presidency on their alliance with the US, which goes back to 1950. A defence ministry official told Yonhap that they will make their utmost efforts to make sure that the existing agreements with the US are carried out as scheduled.

During the campaign, Trump said that he would consider withdrawing US military positioned in South Korea unless Seoul paid a greater share of the cost for the deployment. Around 28,500 troops are stationed in South Korea in combined defense against North Korea.