A U.S. government envoy says Washington and Beijing agree that any North Korean nuclear test will lead to North Korea's further isolation and set back efforts to restart regional talks.

After talks in Beijing with senior Chinese officials, U.S. envoy for North Korea Glyn Davies said Friday that both sides are opposed to North Korea's conducting a nuclear test.

Davies' Beijing trip comes as tensions are rising and China is showing signs it wants to rein in its North Korean ally. Beijing and Washington backed a U.N. resolution this week to tighten sanctions against North Korea as punishment for last month's rocket launch. In response, North Korea warned it is prepared to conduct a nuclear test.