The two Koreas on Monday restored their hotlines that the North severed months ago, with Pyongyang urging Seoul to step up efforts to improve relations after criticising what it called double standards over weapons development.
North Korean leader Kim Jong Un expressed his willingness last week to reactivate the hotlines, which North Korea cut off in early August in protest against joint South Korea-US military exercises, just days after reopening them for the first time in a year.
Pyongyang's official KCNA news agency had said the telephone links would be reconnected on Monday at 9:00 a.m. (0000 GMT).
The South confirmed that twice-daily regular communication was restarted on time via military hotlines and others run by the Unification Ministry, except for the navy channel set up on an international network for merchant ships.
The hotlines are a rare tool to bridge the rivals, but it was unclear whether their reconnection would facilitate any meaningful return to talks aimed at dismantling the North's nuclear and missile programmes in return for US sanctions relief.
KCNA called for Seoul to fulfil its "tasks" to mend strained cross-border ties, repeating Kim's speech last week that he had decided to recover the lines to help realise people's hopes for a thaw and peace.
In that speech, Kim urged South Korea to abandon its "double standards" and "delusion" over the North's self-defensive military activities while developing its own weapons.
"The South Korean authorities should make positive efforts to put the north-south ties on a right track and settle the important tasks which must be prioritised to open up the bright prospect in the future," KCNA said.
HOTLINES REDUCE TENSIONS
Seoul's defence ministry said the hotlines have contributed to preventing unexpected clashes and their reopening would hopefully lead to substantive easing of military tension.
The Unification Ministry, responsible for inter-Korean affairs, expressed hopes that it would be able to resume dialogue soon on ways to recover relations and foster peace.
In Washington, a US State Department spokesperson said it strongly supports inter-Korean cooperation, calling the reconnected lines "an important component in creating a more stable environment on the Korean Peninsula."
Tension had flared since the hotlines were severed, with North Korea warning of a security crisis and firing a series of new missiles, including a hypersonic missile, an anti-aircraft missile, and a "strategic" cruise missile with potential nuclear capabilities.
The launches underlined how the isolated country has been constantly developing increasingly sophisticated weapons, raising the stakes for stalled denuclearisation negotiations.
While accusing Washington of "hostile policy," Pyongyang has said it is willing to mend inter-Korean relations and consider another summit if Seoul drops double standards.
Analysts say the North's carrot-and-stick approach is aimed at securing international recognition as a nuclear weapons state and driving a wedge between the United States and South Korea, counting on South Korean President Moon Jae-in's eagerness to forge a diplomatic legacy before his term ends in May.