While the U.S. and North Korea have presented different accounts of why the summit failed, "both sides believe that the lifting of sanctions is an important component of the denuclearization process," Chinese foreign ministry spokesman Lu Kang said at a regular news briefing.
Lu added that China welcomes the "positive will" expressed by the U.S. and North Korea to maintain communications.
In his post-summit news conference in Hanoi on Thursday, President Donald Trump praised Chinese leader Xi Jinping for being "very helpful" with North Korea. Trump said Xi told him that he doesn't "love having a nuclear state right next to China."
China is North Korea's most important ally, but has agreed to increasingly strict United Nations sanctions over the North's programs to develop nuclear weapons and ballistic missiles to deliver them.
North Korean Vice Foreign Minister Ri Kil Song met with Chinese Foreign Minister Wang Yi in Beijing on Thursday shortly after the abrupt end to the U.S.-North Korea summit.
While traditionally close ties between the two countries have frayed somewhat, Xi hosted North Korean leader Kim Jong Un three times in China last year, both before and after Kim's first meeting with Trump in Singapore.