KAESONG, NORTH KOREA (REUTERS, AFP) - North and South Korea opened a liaison office on the North's side of their heavily militarised border on Friday (Sept 14), setting up a permanent channel of communication as part of a flurry of efforts to end their decades old rivalry.

Steps by North and South Korea to improve their relations are running parallel to a bid by the United States and its allies to press North Korea to give up its nuclear weapons and ballistic missile programmes.

The opening of the joint liaison office at Kaesong, just inside the North Korean side of the border, comes days before North Korean leader Kim Jong Un and South Korean President Moon Jae-in are due to hold their third meeting this year.

"A new chapter in history is open here today," South Korean unification minister Cho Myoung-gyon said at a ceremony, according to a pool report. "This liaison office is another symbol of peace jointly created by the South and the North."

"The two sides are now able to take a large step toward peace, prosperity and unification of the Korean peninsula by quickly and frankly discussing issues arising from inter-Korean relations," said Ri Son Gwon, the head of North Korea's delegation at the opening ceremony.

The building includes separate Northern and Southern offices and a joint conference room, and is intended to facilitate cross-border exchanges following the Panmunjom Summit between Mr Moon and the North's leader Kim Jong Un, the unification ministry said.

The two Koreas previously communicated by fax and special telephone lines, which were often severed when their relations took a turn for the worse. Now they will now be able to "directly discuss issues 24 hours, 365 days", Mr Cho said at the ceremony.

Seoul and Pyongyang have sought to pursue joint projects in multiple fields since their April summit in the Demilitarised Zone that divides the peninsula, even as US efforts to secure concrete progress towards North Korea's denuclearisation have stalled.

Mr Moon is due in the North's capital next Tuesday for a three-day visit, his third summit with Mr Kim this year after he orchestrated a rapid diplomatic thaw on the peninsula and brokered June's Singapore summit between the North Korean leader and US President Donald Trump.

There, Mr Kim backed denuclearisation of the "Korean peninsula", but no details were agreed and Washington and Pyongyang have sparred since over what that means and how it will be achieved.

The North was "willing to denuclearise", Mr Moon said on Thursday, while the US was willing to "end hostile relations" and provide security guarantees, "but there is a blockage, as both sides are demanding each other to act first".

It is hoped the upcoming meeting between Mr Moon and Mr Kim can help end an impasse between the United States and North Korea.

Weekly meetings

The joint liaison office will be staffed by up to 20 people each from the two sides with the South Koreans on the second floor and the North Koreans on the fourth floor of the four-storey building.

Vice minister-level officials will head their teams at the office and will attend weekly meetings, the South Korean Unification Ministry said.

The office is at the site of the Kaesong industrial complex, where for about a decade, South Korean companies ran production lines staffed by North Korean workers at the industrial park.

The park, once the most striking symbol of inter-Korean cooperation, has been closed since February 2016 when tension on the peninsula spiked after North Korea conducted its fourth nuclear test.

South Korea's Unification Ministry spokesman Baik Tae-hyun said this week it was hoped the liaison office could also help the United States and North Korea in their negotiations.

"We hope that this will also help the progress of denuclearisation talks between North Korea and the United States," Baik said.

South Korea had hoped to open the office by August but it was delayed when denuclearisation talks between the United States and North Korea stalled.

However, Mr Kim sent a message to South Korean envoys last week saying he wanted to achieve denuclearisation during Mr Trump's first term.

That followed what Mr Trump described as a "very warm" letter from Mr Kim requesting another meeting, which rekindled hopes for progress.