U.S. Secretary of State Rex Tillerson and Secretary of Defense James Mattis both participated in high level talks with Chinese government officials in Washington D.C. on Wednesday.  The meeting saw American diplomats joining with defense officials in their calls for the Chinese government to increase economic and diplomatic pressures on Kim Jong Un’s North Korean regime, specifically in regard to their pursuit of nuclear weapons and ballistic missile platforms capable of delivering them.

The Chinese delegation in the meeting included State Councilor Yang Jiechi and General Fang Fenghui, chief of joint staff of the People’s Liberation Army.

On Tuesday, President Trump took to Twitter to declare that China’s efforts to press Kim into giving up his pursuit of weapons of mass destruction has been a failure, though he tempered his statement with an acknowledgement that he believes President Xi tried.

“While I greatly appreciate the efforts of President Xi & China to help with North Korea, it has not worked out,” President Trump wrote on Twitter the night before Chinese officials arrived in Washington D.C. “At least I know China tried!”

The death of Otto Warmbier, an American student who spent 17 months as a North Korean prisoner before being released last week in a vegetative state, has only further weakened relations between the United States, whom China has accused of being too aggressive in the Pacific, and Kim’s regime.

The United States has repeatedly called on China to take a more proactive position in dealing with North Korea.  As the reclusive state’s primary and most powerful ally, China accounts for nearly ninety percent of North Korea’s import and export market, placing them in the unique position of being the only nation with significant leverage over Kim Jong Un.  China has continued to counter U.S. requests, claiming the onus is not on China alone to convince North Korea’s Supreme Leader to do away with his nuclear ambitions.

Despite China’s Foreign Ministry claiming that their government has made “unremitting efforts” to resolve tensions on the Korean peninsula, the United States government has been clear that they would like to see China institute an oil embargo and bans on North Korean airlines flying in and out of Chinese cities, among other sanctions.

China’s statement also including language suggesting that their efforts regarding North Korea have not been brought about by external pressures from Trump’s White House, but rather were because China is a “responsible member of the international community.”