DANDONG, China — Trucks rumbled across the Chinese-North Korean border Thursday in a sign that trade was continuing despite Beijing’s anger over the North’s avowed hydrogen bomb test, which could spark economic retaliation and further estrangement between the once-close communist allies.

There were no obvious signs of disruption in the northeastern city of Dandong that sits on the Yalu River directly across from North Korea’s Sinuiju. The twin cities are the conduit through which much of North Korea’s international trade passes.

China condemned Wednesday’s purported test, which sent tremors across parts of northeastern China near the North Korean border and alarmed residents.

“I think it is a threat and sabotage to China and to the world peace for such a country to own nuclear weapons,” Dandong resident Tian Zhibin said in an interview with The Associated Press on Thursday.

Analysts say Beijing will likely join other members of the U.N. Security Council in imposing tougher economic sanctions on its communist ally.

Beijing could also introduce unilateral measures such as tighter inspections of the trucks that cross the Yalu carrying mostly consumer goods bound for the North. China-North Korean economic projects could be suspended and Chinese companies and banks discouraged from doing business with North Korea.

Yet as North Korea’s neighbor and chief backer, Beijing is unlikely to takes steps that might seriously undermine Kim Jong Un’s hard-line communist regime. Apart from a traditional friendship dating back decades, China is fearful of a collapse that could bring chaos, sending refugees across the border and possibly leading to a U.S. military presence in the North.

Although willing to notch up sanctions, Beijing likely won’t reduce energy and food assistance or impose overly harsh economic sanctions, said Bonnie Glaser, an expert on China at the Center for Strategic and International Studies think tank.

“Economic relations and nuclear issues are likely to remain on two separate tracks,” Glaser said.

Despite the ups and downs in relations, China continues to have a vested interest in maintaining friendly ties with Pyongyang. Apart from providing material assistance, that includes defending North Korea from condemnation at the United Nations over its human rights abuses and designating refugees from the North as economic migrants rather than asylum seekers.