YANJI, China (Kyodo) -- Chinese state banks have started suspending transactions through accounts held by North Koreans, making it nearly impossible to do business between the two countries, sources familiar with the situation said Saturday.
Kyodo News has confirmed that branch offices of at least three major state banks -- the Bank of China, China Construction Bank and Agricultural Bank of China -- in the northeastern border city of Yanji have also banned North Koreans from opening accounts.
The Chinese banks have yet to freeze the accounts, meaning that North Koreans can still withdraw money from them, but they are now prevented from making deposits or remittances, according to the sources speaking on condition of anonymity.
"This is being influenced by international sanctions against North Korea," an employee of one bank said.
The bank restrictions, which the sources said from April were also starting to be put in force in Liaoning Province -- the main region of trade between China and North Korea -- suggest that China may have become more serious about curbing its nuclear ambitions.
The restrictions also appear to be intended to help major Chinese banks avoid being hit by sanctions imposed by the United States and other countries.
In late June, the administration of U.S. President Donald Trump labeled a regional bank based in the northeastern border city of Dandong "a foreign bank of primary money laundering concern," and unilaterally sanctioned another Chinese firm and two Chinese individuals for links to Pyongyang's arms development.
The United States now seeks to impose the toughest U.N. sanctions possible on North Korea in the wake of its sixth nuclear test a week ago and calling on China to do more to rein in its defiant neighbor.
In response to the Sept. 3 nuclear test, the United States and its allies are pushing to have the U.N. Security Council include an oil embargo and a freeze on North Korean leader Kim Jong Un's assets in a set of new sanctions.
China, which accounts for about 90 percent of North Korea's official trade and is its major oil supplier, has long opposed taking excessively strict measures against the country, out of fear of triggering a refugee crisis on the border.
China's official data show that its exports to North Korea of petroleum products, including gasoline and light oil but excluding crude oil, fell 75 percent in three months through July from a year earlier to about 19,700 tons.
One source said the main reason for the decline was that North Koreans were having difficulty paying for petroleum product imports because of the banking restrictions.
In North Korea, gasoline prices shot up in April and remain high.
North Korean officials told Kyodo News in July that economic activity was not in a state of confusion and prices were not rising continuously.
But they said the government had encouraged North Koreans to use public transportation and bicycles to conserve fuel.