North Korea’s public reaction prompted speculation about a possible link to the Syrian target, though whether the target involved nuclear activity, missiles or something else remained unknown to all but a handful of officials briefed on what had happened.

This week China abruptly canceled a new round of diplomatic talks that had been planned to discuss a schedule for disbanding North Korea’s nuclear facilities under a deal negotiated in February. It is not clear when those talks may resume.

Mr. Bush said Thursday that the United States expected the North Koreans “to honor their commitment to give up weapons and weapons programs, and to the extent that they are proliferating, we expect them to stop that proliferation.”

Some current and former American officials, who spoke on the condition of anonymity because information about the raid remained classified, said they believed that the site was involved in Syria’s missile program. They said that Israeli intelligence officials believed that they had evidence that the activity at the site involved North Korean engineers believed to work in the nuclear program.

So far, several current and former American officials who have been involved in evaluating the Israeli claims say they are not yet convinced of a nuclear connection. Yet the enormous secrecy around the findings, both here and in Israel, suggests that the activity that prompted the Israeli attack involved “more than a run-of-the-mill missile transaction,” one official said, noting that the Israelis took considerable risks in carrying out the attack.

“The Israelis are very proud of what they are doing; they are boasting about it,” said one senior American official who has been dealing with Israeli officials. “But we don’t know enough yet about what they actually hit.”

In Israel, military censors have prohibited the press from reporting any details, while Prime Minister Ehud Olmert’s government has succeeded in remaining silent about the raid. The head of Israel’s military intelligence, Gen. Amos Yadlin, appeared to refer to the matter obliquely when he told the cabinet that Israel had “restored its deterrence” in the region.