The United States won't "intervene" if South Korea decides to send food aid to North Korea, the White House said Wednesday.

US President Donald Trump expressed support for South Korea's possible humanitarian assistance to the North during a phone call with President Moon Jae-in on Tuesday, the latter's office said.

White House press secretary Sarah Sanders was asked at a meeting with reporters Wednesday if Trump will go along with the plan despite the North's firing of projectiles last week.

"Our position in regards to North Korea is going to continue to be the maximum pressure campaign. Our focus is on the denuclearization," Sanders said, referring to the US-led sanctions aimed at dismantling the North's nuclear weapons program.

"If South Korea moves forward on that front, we're not going to intervene," she added.

An estimated 10 million people in North Korea, or 40 percent of the population, are in urgent need of food, according to a recent joint report by the World Food Program and the Food and Agriculture Organization.

Delivery of humanitarian assistance to the impoverished nation has often been hampered by international sanctions imposed on the regime for its nuclear and ballistic missile programs.

In 2017 the South Korean government set aside US$8 million in humanitarian aid for the North, but the plan never materialized amid the North's continued provocations at the time.

A South Korean presidential official told reporters Wednesday that the government has yet to determine the exact size of food assistance and its means of delivery.

US Special Representative for North Korea Stephen Biegun arrived in Seoul Wednesday for talks with his South Korean counterpart, Lee Do-hoon.

The two are expected to discuss ways to resume stalled denuclearization negotiations between Washington and Pyongyang, as well as the issue of food aid. (Yonhap)