Both Seoul and Washington appear keen to use Trump's looming trip to China as a springboard for diplomacy with Pyongyang -- and analysts believe recent sanctions relief could get their foot in the door.

South Korean President Lee Jae Myung has been particularly keen to mend ties with the North, although his overtures have so far been largely ignored.

"These exemptions are certainly aimed at signalling to Pyongyang that Seoul isn't going to give up any opportunity for a dialogue with North," foreign affairs expert Minseon Ku told AFP.

"The Lee administration has been pursuing the creation of a diplomatic space for Trump and Kim to meet since Lee's visit to Washington last August," said Ku, from DePaul University in Chicago.

North Korea's economy has for years languished under heavy Western sanctions on everything from oil to seafood, measures that aim to choke off funding for its nuclear weapons programme.

A UN Security Council committee recently approved exemptions allowing fresh flows of food and medicine into North Korea, diplomatic sources told AFP last week.

With the move, Washington and Seoul "are essentially removing a technical and moral alibi for Pyongyang's refusal to engage. It is a low-cost, high-optics maneuver," Seong-Hyon Lee, a visiting scholar at the Harvard University Asia Centre, told AFP.

Trump is expected to visit North Korea's longtime ally China in April.

Speculation is mounting he may seek some kind of meeting with Kim on the sidelines of that visit.

Ku said Trump would be eager to display his diplomatic prowess by securing a rare photo op with Kim.

- Nuclear negotiations -

Trump met Kim three times during his first term -- once declaring they were "in love" -- as he pushed to hammer out a long-coveted deal on de-nuclearisation.

Their highly anticipated Hanoi summit in 2019 collapsed over differences about what Pyongyang would get in return for giving up its nuclear weapons.

No tangible progress has been made between the two countries since then.

Trump stepped up his courtship of Kim during a tour of Asia last year, saying he was "100 percent" open to a meeting.

He even bucked decades of US policy by conceding that North Korea was "sort of a nuclear power".

But Kim has so far refused to take the bait.

"Like any negotiating party, North Korea dislikes unpredictability and uncertainty," said Lim Eul-chul from the Institute for Far Eastern Studies at Kyungnam University.

"Trump is not seen as a reliable partner, and Pyongyang may be buying time to maximise its leverage."

North Korea's ruling Workers' Party is preparing to hold a rare congress later in February.

The gathering, typically held just once every five years, will be closely watched for any signs of a shift in foreign policy.

At the last congress in 2021, Kim declared the United States was North Korea's "principal enemy".

Kim appeared alongside China's Xi Jinping and Russia's Vladimir Putin at a grand military parade in Beijing last year -- a striking display of his powerful friends and elevated status in global politics.

He may seek to engage with Trump in a similar vein to Putin, who has sought to find areas of economic cooperation despite intense strategic competition, said Korea scholar Vladimir Tikhonov.

"It can be a good model for Kim -- talking to the US does not (have to be) surrender," he told AFP.