FILE PHOTO - A discarded syringe is seen under a bridge on Lester Avenue in Johnson City, New York, U.S., April 7, 2018. REUTERS/Andrew Kelly

BEIJING (Reuters) - China’s drug control agency on Monday said the United States should do more to cut its demand for opioids to tackle the use of synthetic drug fentanyl, but it vowed to step up cooperation after Chinese production of the substance had been blamed for fuelling the U.S. opioid crisis.

U.S. President Donald Trump said in November on a state visit to Beijing that China and the United States would do more to stem what he called a “flood of cheap and deadly” fentanyl “manufactured in China” from entering the United States.

A year-long congressional probe into the use of fentanyl in the United States found that the substance could easily be bought online from Chinese “labs” and mailed to the United States due to gaps in oversight in the U.S. Postal Service.

“China’s drug control agencies, now and in the years to come, will place greater emphasis on drug control cooperation between China and the United States,” Liu Yuejin, deputy head of China’s National Narcotics Commission, told a news conference.

“But I believe that to resolve this the more important issue is for the United States to strive to reduce and compress the great demand and drug consumption markets of opioids,” he said.

While China accepts that some new psychoactive substances, including fentanyl, manufactured in China are sold in the United States, the substances are not yet readily abused and trafficked in China itself, he said.

Asked whether joint efforts between China and United States would be impacted by current tensions in the bilateral relationship, Liu said that political factors would not affect China’s resolve to combat drug manufacture and trafficking.

According to the U.S. Centers for Disease Control and Prevention, opioids were responsible for more than 33,000 U.S. deaths in 2015. Fentanyl is 50 times more potent than heroin and 100 times more potent than morphine.

Beijing has taken steps to crack down on the production and export of synthetic drugs, and has placed fentanyl and 22 other related compounds on its list of controlled substances.