"President Trump reiterated our ironclad commitment to defend the ROK (Republic of Korea), including through the provision of extended deterrence, using the full range of military capabilities", AFP quoted the White House as saying in a statement".
On Sunday, Trump and Hwang held a phone conversation and discussed a number of issues, including the existing alliance between the two countries.
North Korea has resumed its indoctrination of South Korean abductees as part of a broader effort by the reclusive regime to tighten control over its people, a local activist group said Monday.
Trump's remarks and reported support for the alliance are notable due to statements made during the campaign trail in which he questioned the value of providing sustained US military support to South Korea.
"The two leaders agreed to take steps to strengthen joint defense capabilities to defend against the North Korean threat".
In early January, President Trump promised that North Korea wouldn't develop a nuclear weapon capable of reaching the US. He said the US and South should take "strong measures based on bilateral cooperation" if the North continues to make "provocations" in spite of repeated warnings from the global community.
North Korea has maintained its nuclear and missile programs in violation of repeated rounds of global sanctions.
One thing that's nearly sure to come up is the implementation of the Terminal High Altitude Area Defense (THAAD) missile system in South Korea. The Republican has been sceptical of Washington's military spending on its allies. He's publicly mused whether it's worth continuing to support Japan and South Korea without reevaluating what the U.S. gets in return.
It said that the first indoctrination courses took place last year after a hiatus of some 30 years.
Hwang has been serving as the acting president since President Park Geun-hye was impeached by parliament over corruption allegations on December 9.
During his campaign, Trump threatened to withdraw USA forces from the two countries if they did not step up their financial support for their defense.