Beijing called on North Korea Tuesday to "adopt a responsible attitude" and avoid fueling tensions over its nuclear test, the South China Morning Post reported. Foreign Ministry spokesman Liy Jianchao also said Pyongyang should "come back to resolving the issue through dialogue and consultation". The comments came as media sources claimed that US officials are concerned North Korea is preparing for a second test. Beijing was also seen as responding to remarks from Pyongyang that the UN sanctions are an act of war which would not be tolerated now it is a nuclear power. Liu said Beijing would implement the UN Security Council resolution and was also imposing financial sanctions on North Korea. The implementation of the UN sanctions came under the spotlight Monday as the US claimed it had the right to intercept cargo shipments to the country. China, wary that this could trigger military clashes, argued that such action was not mandatory under the sanctions.