China's Foreign Ministry has called for all sides to show restraint over North Korea's announcement that it plans to launch a rocket in defiance of U.N. sanctions.

Ministry spokesman Lu Kang also expressed skepticism Wednesday over calls by the U.S. for tough new sanctions against North Korea over its Jan. 6 nuclear test.

Lu's comments come as U.S. diplomats are urging China to use its political and economic influence with North Korea to compel it to stop such actions.

China has pushed back against U.S. calls for tougher sanctions. Foreign Minister Wang Yi argued during a visit last week by U.S. Secretary of State John Kerry that sanctions are not an end unto themselves and any new U.N. resolution should not provoke new tensions or destabilize the Korean Peninsula.