TOKYO, Aug. 2 Kyodo - Parties to six-way talks aimed at resolving the North Korean nuclear standoff have begun trying to set a working group meeting for Aug. 17-20 in Beijing ahead of the fourth round of plenary discussions, sources close to the talks said Monday.

China, which has been hosting the six-party talks, has sounded out the other parties -- Japan, the United States, Russia, North and South Korea -- about the time frame, the sources said.

The venue is expected to be Beijing, which is where the previous six-way meetings have been held, the sources said. The participants plan to hold the fourth round by the end of September.

Ning Fukui, China's ambassador in charge of the North Korean nuclear issue, is expected to propose the schedule to Japan when he visits Japan later this week, and Japan is likely to agree to it, the sources said.

Aug. 17 may be allocated for bilateral meetings among the member countries, and the working group meeting itself may begin the following day, they said.

At the discussions, the participants are expected to exchange opinions on Pyongyang's call for energy aid in exchange for freezing its nuclear programs and the North's request for a security guarantee.

The U.S. proposal of a three-month ''preparatory period'' to dismantle Pyongyang's nuclear programs, which was laid out in the third round of talks in June, is also expected to be discussed at length, the sources said.

The third round of talks in Beijing ended with no major breakthrough, but the members agreed to hold a fourth round by the end of September and convene working group meetings prior to that.

The United States, Japan and South Korea have repeatedly called for complete dismantlement of all North Korea's nuclear programs, but Pyongyang wants to hold on to those it says are for peaceful use, including energy purposes.

The nuclear crisis erupted in October 2002 when the United States said North Korea had admitted to running a secret uranium enrichment program in violation of international agreements, including a 1994 nuclear accord between Washington and Pyongyang. ==Kyodo