US PRESIDENT BARACK OBAMA has called his Chinese counterpart Hu Jintao and appealed to him to intervene in the growing tensions between North and South Korea, asking him to rein in China’s northern ally.

In a call that had been repeatedly delayed due to ‘scheduling issues’, the White House said Obama had “asked China to “send a clear message to North Korea that its provocations are unacceptable.”

Obama also asked Hu to work with the US and other countries in resolving the difficulty, and other international conflicts such as the emerging worries over Iran’s nuclear threat.

In the phone call, Hu said China was “highly concerned” over the Korean situation, which had the potential to spiral out of control if it was not dealt with appropriately.

China’s news agency Xinhua said Hu asked for a “cool and rational” response.

The Chinese comments came just as South Korea began a major military live-fire exercise, in spite of North Korea’s warnings that such drills would be considered a provocation and could induce further response.

The conflict has been ongoing for the past 13 days, since North Korea bombed a southern island, when four people including two civilians were killed under artillery fire.

The New York Times believes, however, that the delay in the conversation between Obama and Hu was down to a frostening in US-Chinese relations, with the two countries apparently hardening their positions on divisive world issues.