North Korea said Friday it has disbanded a special committee that was set up in 2014 to look into the whereabouts of missing Japanese who are suspected of being abducted decades ago, in response to Tokyo’s decision earlier in the week to impose new sanctions on Pyongyang.

The announcement, conveyed by the state-run Korean Central News Agency, denounced the Japanese government’s decision as “provocative” and threatened that it would entail “stronger countermeasures,” without specifying what that would involve.

Japan announced Wednesday it will expand sanctions on North Korea to punish Pyongyang for launching a long-range rocket Feb. 7, which is widely viewed as a test of ballistic missile technology, and conducting a fourth nuclear test on Jan. 6, both in defiance of U.N. Security Council resolutions.

Japan’s new measures include banning remittances to North Korea in principle and stopping ships from entering Japan after visiting North Korea, which has never had diplomatic relations with Tokyo.

For Japan, the abduction issue has been a sticking point in its relations with North Korea for many years.

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Japan officially lists 17 nationals as having been abducted by North Korean agents in the 1970s and 1980s, but suspects the North’s involvement in many more disappearances.

While five of the 17 were repatriated in 2002, Japan continues to seek the return of the remaining 12.

Of those 12, Pyongyang claims eight have died and four never entered the country.

In July 2014, Japan partially lifted its unilateral sanctions on North Korea in return for its establishment of the special investigative committee.

The committee had a “special mandate” from the National Defense Commission, led by North Korean leader Kim Jong Un, and Pyongyang had initially said it would complete its probe within a year or so.

But according to Japanese officials, North Korea did not provide any convincing initial findings from the investigation after the establishment of the committee, and there had been no tangible progress on the abduction issue.

The committee said in a statement carried by the official news agency that it was North Korea’s legitimate right as a sovereign state to launch the rocket and conduct the nuclear test, and that Japan is not in a position to criticize the actions.

The panel said Japanese Prime Minister Shinzo Abe’s government has to hold “full responsibilities for causing such a grave consequence as today’s” by reapplying the lifted sanctions and rolling out fresh punitive measures.

“The comprehensive investigation into all the Japanese that had been under way under the inter-governmental Stockholm agreement will be totally stopped,” it said, adding that North Korea has recognized the sanctions as Tokyo’s declaration of scrapping of the accord.

Japan and North Korea announced in May 2014 that they had reached an agreement in Stockholm on the guiding principles of negotiations toward the settlement of their outstanding issues.

In Tokyo, a senior official of Abe’s government said North Korea’s announcement was “within expectations” and that Japan will have to take a wait-and-see stance as it watches developments in Pyongyang.

Another official said that despite the stalemate, Japan will tackle the abduction issue “tenaciously,” pointing out Tokyo’s principle of “action for action” in dealing with Pyongyang.