South and North Korea produced an agreement on defusing heightened tensions, Seoul's top negotiator said Tuesday, in a dramatic breakthrough after days of intensive high-level talks.

North Korea expressed regret over its landmine attack and promised to make efforts toward provocations not recurring, National Security Adviser Kim Kwan-jin told reporters after returning to Seoul from the border village of Panmunjom.

Kim described the North's move as "very meaningful."

President Park Geun-hye said South and North Korea should follow through on their breakthrough deal to ease tensions and improve strained relations.

"I hope that the deal could serve as an occasion to resolve all inter-Korean issues through trust," Park said in a message read by her spokesman, Min Kyung-wook.

The deal came hours after Park warned South Korea would take measures and continue propaganda broadcasts unless North Korea offered a clear apology and promised not to stage any more provocations.

Tensions between the Koreas had risen dramatically in recent weeks after South Korea accused North Korea of being behind a landmine attack that maimed two South Korean soldiers.

The North also fired artillery shells across the border last Thursday, prompting South Korea to fire back dozens of shells.

The North had denied responsibility in the landmine attack.

But North Korea later backed down from its adamant position during the negotiations that ended early Tuesday, clearing a key stumbling block to the deal. The two sides began the talks on Saturday evening.

Kim said South Korea made a persistent demand for the prevention of recurrence of provocations to break a vicious cycle of North Korea's provocations.

For decades, North Korea has a track record of carrying out provocations against South Korea, including the sinking of a South Korean warship and the shelling of a South Korean border island, both in 2010 that killed 50 South Koreans.

In return for the North's expression of regret, South Korea agreed to stop anti-Pyongyang broadcasts along the heavily fortified border as of 12 p.m. Tuesday unless an abnormal situation occurs, Kim said.

South Korea resumed the propaganda broadcasts earlier this month for the first time in 11 years in retaliation against North Korea for the landmine attack.

North Korea has repeatedly called for the end of the broadcasts critical of North Korean leader Kim Jong-un, viewing them as an insult to its dignity. The isolated country is also concerned that an influx of outside information could pose a threat to its young leader.

In a sign of defusing tensions, North Korea said it will lift the semi-war state it had imposed on its military during the latest standoff.

The United States also hailed the breakthrough deal.

"We support President Park's tireless efforts to improve inter-Korean relations, which support peace and stability on the Korean Peninsula," State Department spokesman John Kirby said at a regular briefing.

South and North Korea also agreed to hold talks in either Seoul or Pyongyang at an early date to improve inter-Korean relations, said Kim, Seoul's top negotiator, noting the sides came up with a basic framework for development of inter-Korean ties.

"We expect the two sides will implement the agreement in good faith and create trust through dialogue and cooperation," said Kim.

Still, Kim declined to comment on whether he discussed with his North Korean counterpart on an inter-Korean summit.

In January, Park held out the prospect of a summit with North Korean leader Kim Jong-un, days after Kim said he is willing to hold summit talks with Park, if proper conditions are met.

Park's two liberal predecessors held summit talks with then North Korean leader Kim Jong-il, the late father of the current leader Kim, in Pyongyang in 2000 and 2007, respectively.

The two Koreas also agreed to hold Red Cross talks early next month to arrange for reunions of families separated since the 1950-53 Korean War.

The two sides hope to stage the reunions around Chuseok, the Korean equivalent of Thanksgiving Day, which is celebrated in both Koreas and falls on Sept. 27.

Park said the two Koreas should "heal the pain of separated families."

U.N. Secretary-General Ban Ki-moon welcomed the agreement.

"I highly appreciate the agreement to hold regular inter-Korean dialogue, and hope that this will serve as a mechanism to effectively manage any problems that may arise on the Korean Peninsula," Ban, a former South Korean foreign minister, said in a statement.

Millions of Koreans remain separated since the Korean War, which ended in a cease-fire, not a peace treaty.

Family reunions are a pressing humanitarian issue on the divided peninsula, as most of the separated family members are in their 70s and 80s, and wish to see their long-lost relatives before they die.

There are no direct means of contact between ordinary civilians of the two countries that remain divided by a heavily fortified border.

In 2014, the two sides held a series of temporary family reunions for the first time in more than three years. (Yonhap)