The United Nations Security Council is set to vote Monday afternoon on a watered-down U.S.-drafted resolution to impose new sanctions on North Korea over its latest nuclear test, diplomats said, but it was unclear whether China and Russia would support it.

The draft resolution appears to have been weakened in a bid to appease Pyongyang's allies Beijing and Moscow following negotiations over the past few days.

In order to pass, a resolution needs nine of the 15 Security Council members to vote in favor and no vetoes by any of the five permanent members — the United States, Britain, France, Russia and China.