US President Barack Obama and Chinese Premier Li Keqiang agreed Monday to "invigorate" cooperation in the UN Security Council and law enforcement channels on North Korea for the sake of a nuclear-free Korean Peninsula, the White House said.

Obama and Li held the meeting in New York on the sidelines of the UN General Assembly, condemning the North's fifth nuclear test, the White House said in a statement. The meeting came as Washington and Beijing have been negotiating fresh sanctions on Pyongyang.

"Both leaders condemned North Korea's Sept. 9 nuclear test and resolved to strengthen coordination in achieving the denuclearization of the Korean Peninsula, including by invigorating cooperation in the United Nations Security Council and in law enforcement channels on North Korea," the statement said.

The statement appeared to suggest active Chinese cooperation in efforts to punish the North.

Cooperation from China is key to putting together any meaningful punishment for the North as it is one of the five veto-holding permanent members of the UN Security Council and the main provider of food and fuel to the impoverished North.

China, the North's last-remaining major ally, has been reluctant to use its influence over Pyongyang for fear that pushing the regime too hard could result in instability in the North and hurt Chinese national interests.

Analysts say that China often increased pressure on the North in the past, especially when Pyongyang defied international appeals and carried out nuclear tests and other provocative acts, but China never went as far as to cause real pain to the North. (Yonhap)