North Korea has agreed to talks with U.S. officials next month over a new missile the communist state has threatened to test-fire--raising questions among diplomats and analysts about whether American and Asian warnings against the firing had prevailed in Pyongyang or the reclusive country had bluffed Washington into diplomatic concessions.

Now American negotiators are puzzling over how to ensure that the talks in Berlin succeed in keeping North Korea from test-firing the long-range missile without provoking criticism that the United States is submitting to blackmail by giving Pyongyang increased trade, aid or other benefits.

U.S. special envoy Charles Kartman will take the American delegation to Berlin on Sept. 7 with at least one achievement: North Korea has agreed to talk, rather than push the launch button right away, on its Taepodong II rocket.

"It's a positive sign North Korea decided to meet bilaterally," State Department spokesman James Foley said Wednesday. "We intend to use this meeting to stress the advantages to North Korea of improving its relations."

The State Department did not assert that North Korea has suspended its launch preparations, and North Korea said nothing publicly about the planned four-day meetings, to which they will send Deputy Foreign Minister Kim Gye Gwan. But a deal was implicit, and diplomats confirm there has been no activity at the launch site since North Korea started sending signals recently that it was willing to talk.

In fact, North Korea has never even shown its trump card. American sources said three weeks ago that fuel had been delivered to the launch site. But, said a Japanese official familiar with intelligence reports, "We haven't seen a missile. There's nothing on the launch site."

All of which adds to the mystery of whether North Korea's test launch of a shorter-range missile last Aug. 31--and its thumping insistence on its "sovereign right" to conduct another test firing soon--was intended to bluff the United States into concessions at the negotiating table. The 1998 firing of the three-stage Taepodong I missile over Japan--which North Korea said was a satellite launch--rattled East Asia and heightened tensions from Tokyo to Washington. Analysts suspect the new Taepodong II may have a range sufficient to reach Hawaii or Alaska, and there is no certainty that Pyongyang has not obtained a chemical, biological or even nuclear warhead.

The United States, Japan and South Korea have responded to the potential Taepodong II launch with coordinated and concerted warnings to Pyongyang. If it test-fires another missile, Pyongyang could lose the food aid it desperately needs to alleviate widespread famine, along with international assistance in developing safe atomic power for civilian use and any hopes of improved diplomatic relations.

The joint warnings of "serious negative consequences" issued by the foreign ministers of the three countries are expected to be amplified by a similar joint statement after a summit meeting in New Zealand Sept. 12 that is to be attended by President Clinton, Japanese Prime Minister Keizo Obuchi, and South Korean President Kim Dae Jung.

"This will just ruin everything," if North Korea fires another missile, said Rep. Tony P. Hall (D-Ohio), who is currently visiting Pyongyang. "There will be a move in Congress to take away everything, including food aid," he said Wednesday in Tokyo.

But Pyongyang has complained, with some evidence, that the United States has not kept promises made in the 1994 Framework Agreement, under which North Korea agreed to forgo development of nuclear weapons in expectation of an opening of trade with the United States and faster development of two power plants, neither of which has happened.

Kartman now must take more than a threat to the Berlin meeting; he must offer something to persuade North Korea to keep the lid on the Taepodong II. But he does so at the risk of furthering a revolt by congressional critics who say North Korea is continuing its bellicose ways despite repeated concessions by the United States.

A U.S. special envoy, former secretary of defense William Perry, approached North Korea four months ago with an offer of improved relations in return for more moderate behavior, but it is not clear if North Korea even replied to the proposal.

"There are a lot of incentives on the table: lifting trade sanctions, increasing trade. That's what North Korea wants," said Hall. But the North Koreans are intractable negotiators, and Hall, who has campaigned steadily for increased humanitarian aid for North Korea, says he is often perplexed at their behavior.

"I just try not to figure them out," he said.