WASHINGTON, Oct. 13 — Israel’s air attack on Syria last month was directed against a site that Israeli and American intelligence analysts judged was a partly constructed nuclear reactor, apparently modeled on one North Korea has used to create its stockpile of nuclear weapons fuel, according to American and foreign officials with access to the intelligence reports.

The description of the target addresses one of the central mysteries surrounding the Sept. 6 attack, and suggests that Israel carried out the raid to demonstrate its determination to snuff out even a nascent nuclear project in a neighboring state. The Bush administration was divided at the time about the wisdom of Israel’s strike, American officials said, and some senior policy makers still regard the attack as premature.

The attack on the reactor project has echoes of an Israeli raid more than a quarter century ago, in 1981, when Israel destroyed the Osirak nuclear reactor in Iraq shortly before it was to have begun operating. That attack was officially condemned by the Reagan administration, though Israelis consider it among their military’s finest moments. In the weeks before the Iraq war, Bush administration officials said they believed that the attack set back Iraq’s nuclear ambitions by many years.

By contrast, the facility that the Israelis struck in Syria appears to have been much further from completion, the American and foreign officials said. They said it would have been years before the Syrians could have used the reactor to produce the spent nuclear fuel that could, through a series of additional steps, be reprocessed into bomb-grade plutonium.

Many details remain unclear, most notably how much progress the Syrians had made in construction before the Israelis struck, the role of any assistance provided by North Korea, and whether the Syrians could make a plausible case that the reactor was intended to produce electricity. In Washington and Israel, information about the raid has been wrapped in extraordinary secrecy and restricted to just a handful of officials, while the Israeli press has been prohibited from publishing information about the attack.

The New York Times reported this week that a debate had begun within the Bush administration about whether the information secretly cited by Israel to justify its attack should be interpreted by the United States as reason to toughen its approach to Syria and North Korea. In later interviews, officials made clear that the disagreements within the administration began this summer, as a debate about whether an Israeli attack on the incomplete reactor was warranted then.

The officials did not say that the administration had ultimately opposed the Israeli strike, but that Secretary of State Condoleezza Rice and Defense Secretary Robert M. Gates were particularly concerned about the ramifications of a pre-emptive strike in the absence of an urgent threat.

“There wasn’t a lot of debate about the evidence,” said one American official familiar with the intense discussions over the summer between Washington and the government of Prime Minister Ehud Olmert of Israel. “There was a lot of debate about how to respond to it.”

Even though it has signed the Nuclear Nonproliferation Treaty, Syria would not have been obligated to declare the existence of a reactor during the early phases of construction. It would have also had the legal right to complete construction of the reactor, as long as its purpose was to generate electricity.

In his only public comment on the raid, Syria’s president, Bashar al-Assad, acknowledged this month that Israeli jets dropped bombs on a building that he said was “related to the military” but which he insisted was “not used.”

A senior Israeli official, while declining to speak about the specific nature of the target, said the strike was intended to “re-establish the credibility of our deterrent power,” signaling that Israel meant to send a message to the Syrians that even the potential for a nuclear weapons program would not be permitted. But several American officials said the strike may also have been intended by Israel as a signal to Iran and its nuclear aspirations. Neither Iran nor any Arab government except for Syria has criticized the Israeli raid, suggesting that Israel is not the only country that would be disturbed by a nuclear Syria. North Korea did issue a protest.

The target of the Israeli raid and the American debate about the Syrian project were described by government officials and nongovernment experts interviewed in recent weeks in the United States and the Middle East. All insisted on anonymity because of rules that prohibit discussing classified information. The officials who described the target of the attack included some on each side of the debate about whether a partly constructed Syrian nuclear reactor should be seen as an urgent concern, as well as some who described themselves as neutral on the question.

The White House press secretary, Dana Perino, said Saturday that the administration would have no comment on the intelligence issues surrounding the Israeli strike. Israel has also refused to comment.