US Secretary of State Condoleezza Rice says North Korea's agreement to return to six-country talks on its nuclear programme is "only a first step".
Ms Rice travelled to the region in a bid to end the impasse
Speaking after meeting Chinese Foreign Minister Li Zhaoxing in Beijing, Ms Rice said progress in future discussions was the real issue.
However, South Korea welcomed the news, saying new talks should bring "substantive progress".
The talks aimed at persuading North Korea to disarm broke off last year.
International concerns escalated after the North announced in February that it possessed nuclear weapons. Pyongyang is demanding aid and security guarantees before it considers disarming.
Speaking to reporters, Mr Li said the parties should "continue to work together on the shared goal" of a non-nuclear Korean Peninsula.
In a statement, the South Korean foreign ministry said the six-party talks should make substantive progress "through serious and concerted negotiations".
Ms Rice is also due to meet Chinese President Hu Jintao, Premier Wen Jiabao and Foreign Minister Li Zhaoxing.
The secretary of state is on a regional tour ahead of six-party talks - which are now due to resume on 25 July.
North Korean state news agency KCNA said on Saturday that Pyongyang had decided to re-open the six-country talks.
The announcement came after its North Korean Vice-Minister of Foreign Affairs Kim Kye Gwan had talks with US Assistant Secretary of State Christopher Hill in Beijing.
A US official accompanying Ms Rice to China confirmed for reporters that the talks would resume in "the week of 25 July".
North Korea pulled out of the talks 13 months ago after complaining about "aggressive" US policy.
It has said it is stockpiling atomic weapons to defend itself from the US.
The US wants North Korea to dismantle nuclear reactors and stop producing atomic weapons - as well as providing verifiable proof of doing so.
China is one of North Korea's few allies in the region.
Ms Rice is due to visit Thailand, Japan and South Korea after leaving Beijing.