The United States on Tuesday sharply criticized China for not enforcing sanctions on North Korea and vowed to step up its own efforts, AFP reported

The State Department launched a new website, DPRKrewards.com, that will offer payouts of up to $5 million for tips to boost sanctions on North Korea, including on businesses in China.

"I want to tell you more are forthcoming," Alex Wong, the US deputy special representative on North Korea, said of sanctions.

Wong acknowledged that Pyongyang has not yet taken "any concrete steps toward denuclearization" and voiced alarm over its unveiling of a massive long-range missile at a parade in October.

"Lifting sanctions and pumping more revenue into the DPRK [Democratic People's Republic of Korea] while its missile and nuclear production facilities continue to hum is something we will never do," said Wong.

Wong mostly took aim at China, as he accused Beijing of ignoring UN sanctions that it itself voted for at the Security Council over its ally's missile and nuclear programs.

"The premature sanctions relief that Beijing can't achieve through the diplomatic front door, it is instead trying to achieve through the back door," Wong said. "The examples of this chronic failure are numerous, growing and worrying."

He said that US vessels provided information to Beijing 46 times since 2019 about North Korean fuel-smuggling in Chinese waters, and in the past year observed 555 cases of North Korean shipments of coal of other sanctioned exports to China.

"On none of these occasions did the Chinese authorities act to stop these illicit imports. Not once," Wong said.

Wong said that 20,000 North Korean workers still worked in China, going against UN-backed efforts to stop what is widely seen as slave labor that the regime exports for revenue.