UNITED NATIONS — Recent reports of cooperation between Syria and North Korea on weapons development, including in the nuclear field, are chilling earlier enthusiasm in Washington about the prospect of North Korean disarmament through diplomacy.

A person identifying himself as a former Syrian military officer who has had access to sensitive military information in Damascus confirmed to The New York Sun yesterday that Syria has been working on a clandestine nuclear program at least since 1986. The former officer added that many North Korean nationals are in Syria in relation to that program. Syrian and North Korean officials have dismissed reports in several press outlets claiming that the target of a September 6 Israeli air raid over Syria was a nascent Syrian nuclear program heavily aided by North Korea.

If Israel indeed hit a target related to such a program, and if, as the Washington Post first reported, the air raid was scheduled several days after a suspicious North Korean delivery arrived in Syria, this would put Pyongyang, which of late has promised to verifiably disarm its nuclear program, in an awkward position. It also may explain the abrupt suspension of a meeting in Beijing, scheduled for today, of six countries involved in the North Korean disarmament diplomacy.

“The North Koreans don’t want to be in the glare in Beijing, explaining what they are doing in Syria,” a former American ambassador to the United Nations, John Bolton, said. Mr. Bolton, who has led the charge against an inclination by some in the State Department to invest enough trust in Pyongyang to offer it incentives in exchange for disarmament, warned about ties between the regimes of Kim Jong-Il and President al-Assad as long as four years ago.

Now he has seized on the newly reported ties between those two leaders to warn against agreeing to one of Pyongyang’s central demands in the six-party talks. “We don’t want to take North Korea off the terrorist list if they support Syria like this,” Mr. Bolton told the Sun yesterday, urging the State Department to avoid any “rush to new talks” before Pyongyang dispels suspicions about its nuclear cooperation with Syria. Mr. Bolton is about to receive some support in Congress, as well. Rep. Ileana Ros-Lehtinen, a Republican of Florida who is the ranking minority member of the House Foreign Relations Committee, is preparing legislation that would condition North Korea’s removal from the State Department’s list of countries sponsoring terrorism on “permanent and verifiable” dismantlement of its nuclear program, a Republican House staffer who requested anonymity said yesterday.

The six-party talks on North Korea were abruptly suspended on Monday, but a State Department spokesman, Sean McCormack, said yesterday that they could resume quickly. “The Chinese have talked to us about the possibility of an envoys-level meeting next week, and we are ready to go next week if everybody else is ready to go,” he said. He said, however, that once talks resume, Washington will not shy away from asking about reports of North Korean arms proliferation. “Can you raise nonproliferation at these talks? Absolutely,” Mr. McCormack said.

The former Syrian military officer, who asked that no identifying marks beyond the initials A.F. be used for this article, was contacted by the Sun yesterday with the help of the president of the Syria Reform Party, Farid Ghadry. Fearing for his life, A.F. declined to say what country he was speaking from.

He claimed that the Pakistani nuclear scientist Abdul Qadeer Khan has visited Syria several times at least since 1989, after being introduced to the Damascus Baathist regime by Libya, a “great friend” of Syria at the time. “I know [Mr. Khan] keeps good relations” with the Syrians, A.F. said. Based on press reports about the northern Syrian location of the Israeli attack, A.F. suggested that the target was an area where “critical arms and materials” that are imported to Syria are stored before being transferred to Lebanon.

He also said Syria possesses the “latest Russian technology in air defense” but that it was reluctant to expose it during the latest attack, because two decades ago such exposure allowed Israel to destroy all Syrian anti-aircraft missiles in the Bekaa Valley.

Since it reported the September 6 raid, Syria has maintained that its air defenses chased the Israeli aircraft away and that, far from bombing any target, the Israelis escaped, dropping fuel tanks to allow a quicker departure. Damascus also denied reports of a North Korean-aided clandestine nuclear program in Syria.

“All this rubbish is not true,” a Syrian cabinet minister who often serves as the regime’s spokeswoman, Bouthaina Shaaban, said. “I don’t know how their imagination has reached such creativity.” Reports of a North Korean connection are “fabricated stories which have no value and truth,” she added. An unidentified North Korean Foreign Ministry spokesman denied the reports as well.