North Korea's nuclear envoy did not talk to reporters before his sudden departure from Beijing.
A statement by host China said the six countries had agreed to meet again "at the earliest opportunity."
The chief U.S. envoy, Christopher Hill, said efforts to end North Korea's nuclear program remained on schedule despite today's suspension.
The three days of talks stalled after the North Korean envoy refused to continue negotiating until $25 million in frozen funds at a Macau-based bank were released.
The funds were frozen under pressure from the United States, which accuses North Korea of money-laundering and counterfeiting.
Their release was part of a February deal under which North Korea agreed to freeze its nuclear program in exchange for aid and security guarantees. The United States said this week that the funds would be released and transferred to a North Korean account in China.
There has been no official word on what has delayed the transfer.
The six-party talks involve the United States, North and South Korea, China, Russia, and Japan.
(compiled from agency reports)