"China always maintains that the fundamental approach to the realization of ensuring peace and stability of the Korean Peninsula should be through dialogue," Hong said, adding China hopes countries will remain calm and maintain peace on the peninsula.

China's response echoed a similar reaction from Russia and followed strong condemnation from the US.

The Japanese government said on Wednesday the rocket passed over its southern island chain of Okinawa around 12 minutes after liftoff.

The timing of the launch seems to have caught some observers by surprise.

Japan expected that the launch would happen next week, after DPRK space officials said that scientists were considering "readjusting" the timing of the launch.

The DPRK had taken down part of the rocket on its launch pad to fix a technical problem.

"It is impossible for the rocket to lift off from the same launch pad in such a short period of time," Eya Osamu, a specialist on Korean affairs at the Organization for Asian Studies at Waseda University, said in a TV interview.

"The information collected by Japan, the US and ROK is questionable," Pyon Jin-il, editor-in-chief of Korea Report, said.

So far, no missile parts have been found in Japanese territory. Tokyo did not activate the Japan-US joint missile defense system, which is designed to intercept incoming missiles.

Jin Canrong, deputy dean at the School of International Studies at Renmin University of China in Beijing, said the launch's timing was significant.

The successful launch has also boosted Pyongyang in its rocket rivalry with Seoul, Jin said.

Late last month, the ROK suspended the launch of its space rocket carrying a satellite after an abnormality was detected in the second stage of the rocket.

The move is also aimed at exerting pressure on the ROK, which insists on setting preconditions for dialogue with the DPRK, and Washington, which has "neglected" Pyongyang under US President Barack Obama, Jin said.

Jin said Washington is likely to seriously push for further sanctions against Pyongyang.

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DPRK rocket launch