North Korea rejected an offer from South Korea to hold talks on the future of the joint Kaesong industrial complex, as tensions persist in the peninsula on the eve of the 101st birth anniversary of North Korea’s founder on Monday.

Pyongyang called the offer to hold talks an “empty, meaningless” act aimed at disguising invasion plans, state media said, according to BBC.

North Korean laborers failed to report for work on April 9 at the Kaesong industrial complex, a few miles inside the border with North Korea, effectively shutting down the last major symbol of cooperation between the hostile neighbors.

The South Korean Unification Ministry, which oversees relations with the North, said it was “regrettable” that Pyongyang had rejected the offer to hold talks, made last week by President Park Geun-hye, Reuters reports. It said the offer would remain on the table.

South Korea’s Defense Ministry said it was on guard against a possible missile launch to coincide with the Day of the Sun, the birth anniversary of Kim Il-Sung, the founding leader and grandfather of current leader Kim Jong-Un, according to Reuters.

Last year, at Kim Il-Sung’s birth centenary, Pyongyang launched a rocket supposedly aimed at putting a satellite into orbit. The rocket failed shortly after take-off.

“North Korea is not believed to have launched a missile on the occasion of the Day of the Sun, of which today’s is the 101st,” ministry spokesman Kim Min-seok told a briefing, Reuters reports. “But the military is not easing up on its vigilance on the activities of the North's military with the view that they can conduct a provocation at any time.”

On Monday, U.S. Secretary of State John Kerry said the U.S. remained “open to authentic and credible negotiations on denuclearization, but the burden is on Pyongyang,” CNN reports.

Speaking at the end of a three-day trip to South Korea, China and Japan that focused on denuclearization of the Korean Peninsula, Kerry said in Tokyo that North Korea “must take meaningful steps to show it will honor commitments it has already made” and the norms of international law.

“The world does not need more potential for war, so we will stand together. And we welcome China's strong commitment ... to the denuclearization of the Korean Peninsula,” Kerry said.

“The stakes are far too high, and the global economy is far too fragile for anyone to allow these inherited problems to divide the region and inflame it,” he added.

A U.S. State Department official said Monday direct talks were not immediately on the cards, "because North Korea has shown no willingness to move in a positive direction,” CNN reports.