North Korea has restarted all nuclear facilities including its uranium enrichment factory at its Yongbyon nuclear complex north of Pyongyang, its atomic research agency said Tuesday, the day after it hinted that it would launch a long-range rocket next month.

The unidentified director of the Atomic Energy Institute said that its staff have continued to make “innovations” to secure the credibility of the North’s nuclear deterrence by relentlessly improving the “quality and quantity of various nuclear weapons.”

He also defended the nuclear development as “self-defense” measures to counter what he called Washington’s hostile policy toward it.

“As the whole world knows, our possession of nuclear arms is a byproduct of the U.S.’ hostile policy toward North Korea,” said the director in an interview with the North’s official Korean Central News Agency.

“Should the U.S. and other hostile forces continue to stick to their reckless and hostile policy, we are fully ready to respond to it through our nuclear weapons at any time.”

His remarks hinted at the possibility of Pyongyang setting off additional provocations including a fourth nuclear test, amid its deepening international isolation and increasing pressure on it to give up its nuclear program, observers said.

The North Korean nuclear issue is expected to be high on the agenda for the Seoul-Washington summit slated for Oct. 16, and potentially for the U.S.-Beijing summit scheduled for Sept. 25.

A day earlier, the North’s space development agency indicated that it would launch a “satellite” on Oct. 10 on the occasion of the 70th anniversary of the foundation of its ruling Workers’ Party.

Seoul, along with its ally Washington, said that any launch using ballistic missile technology would contravene a set of U.N. Security Council resolutions. It also stressed that any launch would be a “grave provocation and military threat.”

Apparently to counter the international criticism, Pyongyang repeated its hitherto position that it has a “sovereign right for peaceful space development.”

“The world will clearly see a series of satellites of (North) Korea soaring into the sky at the times and locations determined by the Central Committee of the Workers’ Party of Korea,” the unnamed chief of Pyongyang’s National Aerospace Development Administration said in an interview with the KCNA.

“Space development for peaceful purposes is a sovereign state’s legitimate right recognized by international law and the Party, and the people of the DPRK (North Korea) are fully determined to exercise this right no matter what others may say about it.”

The administration’s chief also said that the North is in the final stage of developing a new earth observation satellite for weather forecasts to “actively” contribute to the nation’s economic development, and that it has made “great strides” in its research to develop geostationary satellites.

Expert analyses of satellite imagery have raised the possibility that the North could launch a rocket, as it has been carrying out construction work to improve facilities at the Dongchang-ri launch site in North Pyongan Province.

Seoul’s Defense Ministry said it has yet to detect any unusual North Korean movements that indicate clear preparations for a rocket launch in the near future.

“We are currently maintaining close cooperation with the U.S. to jointly detect any North Korean activities with regard to its possible long-range rocket launch,” ministry spokesperson Kim Min-seok told reporters.

Seoul’s Foreign Ministry warned that should the North launch a rocket, it would deal with the issue at the UNSC in a “prompt and effective” manner.

The North’s mention of a potential rocket launch came as the two Koreas were preparing for the reunions of separated families from Oct. 20-26 at Mount Geumgangsan for the first time since February 2014.

On Tuesday, the two sides exchanged their lists of family members, a process to confirm the final lists of those who will attend the family reunions at the east coast mountain resort.

Observers say that should the inter-Korean relations deteriorate due to a rocket launch around Oct. 10, the reunions could be delayed or canceled. The reunions, planned for September 2013, were delayed just several days before the due date, amid cross-border tensions.

It is also expected to test Seoul’s judgement call as it had pledged to halt propaganda broadcasts, strongly opposed by the North, unless any “abnormal situation” occurs in their landmark Aug. 25 agreement that quelled cross-border military tension this summer.

Experts say that the North might feel the increasing “technological need” to conduct a rocket test to further advance its missile technology, given that it has not carried out any long-range rocket test since December 2012.

“The most crucial reason for the North to want to conduct a rocket test is its technological motive. As the North seeks to become a strong nation in terms of its rocket and nuclear weapons capabilities, additional tests are, obviously, necessary,” said Kim Tae-woo, North Korea expert at Dongguk University.

“We can also think about the domestic political purposes. North Korean leader Kim Jong-un needs to further tighten his grip on power … in other words, to consolidate his leadership authority and strengthen discipline among his people.”

Cheong Seong-chang, a senior research fellow at the think tank Sejong Institute, called on Seoul to make more active efforts to dissuade Pyongyang from a rocket launch that could escalate cross-border tensions and lead to stronger international sanctions that would cause the isolated regime to consider a fourth nuclear test.

By Song Sang-ho (sshluck@heraldcorp.com)