At the request of the United States, the council held urgent closed-door consultations after North Korea's unsuccessful launch earlier in the day of two medium-range missiles, as fears grew that the secretive country was preparing to conduct a fifth nuclear test.
North Korea has now made three bids in two weeks to test-fly a Musudan missile, which is capable of striking US bases on the Pacific island of Guam.
"We are looking at a response," China's Ambassador Liu Jieyi, who holds the Security Council presidency this month, told reporters.
The 15-member council was unanimous in condemning the latest launches, Yoshikawa said.
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Current UN resolutions bar North Korea from developing any ballistic missile-related technology, and South Korea said it would push for fresh penalties to be slapped on Pyongyang.
Diplomats said they expected the council to issue a statement on Friday after the Chinese delegation requested time to consult with officials in Beijing.
Chinese President Xi Jinping on Thursday underscored Beijing's commitment to enforcing existing UN sanctions on North Korea and to preventing any instability on its doorstep.
South Korea said a first launch Thursday of what was understood to be a Musudan missile saw the rocket plunge back to earth seconds after take-off.
A second attempt in the evening -- again of a Musudan -- also appeared to have failed, a defense ministry official said.
An initial effort on April 15 -- the birthday of late founding leader Kim Il-Sung -- ended in what the Pentagon described as "fiery, catastrophic" failure, with the missile apparently exploding just after take-off.