One of China’s biggest banks says it has shut the account of North Korean bank accused by the US of financing the regime’s nuclear program, in the latest sign of Beijing’s displeasure with its neighbor.

The state-owned Bank of China has notified the Foreign Trade Bank of North Korea, the country’s main foreign-exchange bank, that its account had been closed, Dow Jones Newswires said Tuesday.

The closure reflects a shift in China’s approach towards its North Korean ally after the United Nations imposed stricter sanctions on the regime over its rocket launch in December and nuclear test in February.

Washington has also urged China to use its leverage to contain the North following a series of bellicose rhetoric from Pyongyang, escalating tensions on the Korean peninsula.

Beijing has expressed support for the UN sanctions on the North but cautioned against “antagonizing” Pyongyang for fear of further destabilizing the region.

“China is simply not going to go very far because it prizes stability over denuclearization, and it has different aims on the peninsula than the US does,” said Stephanie Kleine-Ahlbrandt, the Beijing-based director of Northeast Asia for the International Crisis Group.