The international community condemned North Korea last week after it put a satellite into orbit using a long-range rocket. Similar launches in 2006 and 2009 coincided with North Korean nuclear tests. A similar effort in April failed.
Washington and Seoul are said to be pressing for a new resolution at the U.N. Security Council condemning the launch, though the Yonhap news agency in South Korea said it's unclear if China will support the measure.
"The U.S. is also sending a message to China that it will have no choice but to beef up its military readiness against North Korea's threats unless a resolution is adopted at the U.N. Security Council," a diplomatic source in Seoul told Yonhap on the condition of anonymity.
Beijing said the launch highlights the need to resume multilateral negotiations with Pyongyang over its nuclear ambitions.
North Korea pointed to the launch as a sign of its growing regional influence.