Members of the U.N. Security Council on Thursday condemned North Korea’s recent ballistic missile launch as a violation of U.N. resolutions and will continue discussions on an “appropriate response,” the council president said.

The remarks were made by Luxembourg’s U.N. Ambassador Sylvie Lucas, president of the 15-nation Security Council for the month of March, after a closed-door meeting on North Korea requested by the United States.

“Members of the Security Council condemned this launch as a violation of Security Council resolution(s),” she said. “Council members agreed to consult on an appropriate response.

“There was unanimous condemnation of the launches,” Lucas told reporters, adding that, “We also all agreed that this response should be given quickly.”

North Korea fired two medium-range Rodong ballistic missiles into the sea at 2:35 a.m. Japan and Korea time on Wednesday (1735 GMT Tuesday), Tokyo and Seoul said.

North Korea’s first firing in four years of mid-range missiles that can hit Japan followed a series of short-range rocket launches over the past two months.

Several council diplomats said negotiations on possible council action would likely continue into next week.

There is a possibility, the diplomats said, of the Security Council’s North Korea sanctions committee expanding the current U.N. blacklist to include additional North Korean entities involved in Pyongyang’s missile program. But they said it could take weeks to reach agreement.

“That (expanding the blacklist) would be an appropriate response by the council,” a Western diplomat told Reuters on condition of anonymity. “The first step will be some kind of more formal statement condemning the launch.”

The ability of the council to take such steps will depend on China, a veto-wielding council member and North Korea’s traditional ally and most significant trading partner. Beijing issued a muted response to the North Korean launch on Thursday.

“In the present situation, all sides ought to dedicate themselves to maintaining peace and stability on the Korean peninsula,” Foreign Ministry spokesman Hong Lei told a regular briefing.

During Thursday’s closed-door council session in New York, Beijing’s delegation reiterated that the Chinese wanted de-nuclearization of the Korean peninsula and to resume stalled six-party aid-for-disarmament talks among the two Koreas, China, Japan, Russia and the United States, a Western diplomat said.

The diplomat, who was inside the closed-door meeting, said China’s delegation also made clear that any council response to North Korea should be proportional to Pyongyang’s actions.

Ballistic missile launches are banned under U.N. Security Council resolutions adopted in response to North Korea’s multiple nuclear tests and rocket firings. The council expanded its existing sanctions after Pyongyang’s February 2013 atomic test, its third nuclear detonation since 2006.

The Security Council’s sanctions on Pyongyang target the country’s missile and nuclear programs and attempt to punish North Korea’s reclusive leadership through a ban on the export of luxury goods to the country.