TEL AVIV, Israel Israel's top military intelligence analyst said Tuesday that the Syrian regime used lethal chemical weapons last month against opposition forces and criticized the international community for failing to act on evidence that "red lines" had been crossed in Syria.
But Secretary of State John Kerry quickly distanced the United States from the assertion, saying that he had spoken Tuesday morning to Israeli Prime Minister Benjamin Netanyahu and that "he was not in a position to confirm" the public Israeli allegations of chemical weapons use in Syria.
"The information I have at this point does not confirm it to me in a way that I would be comfortable commenting on it as a fact," said Kerry, who was in Brussels for a NATO conference. "But obviously, whatever allegations are made have to be thoroughly investigated, and it is appropriate to chase this one down and find out what's going on, no question about it."
Defense Secretary Chuck Hagel, who left Israel for Amman, Jordan, on Tuesday, made no public comment on the allegation, but his spokesman, George Little, indicated that the United States was not yet convinced.
"The United States continues to assess reports of chemical weapons use in Syria," he said. "The use of such weapons would be entirely unacceptable."
Determining whether the Syrian government has used chemical weapons in its two-year war against rebel forces could be critical to whether the United States becomes engaged militarily in the battle there. President Barack Obama has called such use a "red line" that would force the United States to act, though precisely what U.S. action would follow has not been spelled out.
Rebel forces, hoping such action would include lethal military aid for their movement, have since August accused the government of President Bashar Assad of using chemical weapons at least half a dozen times in Damascus and Aleppo, but those incidents have not been confirmed.
In March, the two sides accused each other of using the weapons in Aleppo, and the Assad government called for an international investigation. A United Nations team is waiting in Cyprus to conduct the investigation, but so far the Assad government has not granted it permission to enter Syria.
Brig. Gen. Itai Brun, chief of research for Israeli military intelligence, told a security conference in Tel Aviv that there was strong evidence that a lethal chemical weapon, likely the nerve gas sarin, had been used in incidents near Damascus and Aleppo on March 19. He said that photographs of victims with foam coming out of their mouths and contracted pupils were signs of sarin use.
An Israeli intelligence officer who reports to Brun added later that additional satellite images and witness testimony had been used to "conclusively determine" that a nerve agent had been used in the attacks.
The officer, who spoke on condition of anonymity because he wasn't authorized to speak publicly, said that Israel was investigating "nearly half a dozen possible incidents" but that its most conclusive findings were over attacks in the Damascus suburbs of Jobar, Adra and Ataibeh.
"To the best of our understanding, there was use of lethal chemical weapons. Which chemical weapons? Probably sarin," Brun told the Institute for National Security Studies, an Israeli think tank with close ties to the government. "There's a huge arsenal of chemical weapons in Syria. Our assessment is that the regime has used and is using chemical weapons."
Last week, the British and French governments sent a letter to U.N. Secretary-General Ban Ki-moon, saying that they believed there was credible evidence that Syria had used chemical weapons since December in or near the cities of Homs, Aleppo and Damascus.
But despite those assessments, skeptics abound. Rami Abdurrahman, who runs the London-based Syrian Observatory for Human Rights, which tracks casualties on both sides of the conflict, said that there was still no evidence confirming chemical weapons use.
He noted that in the March attack in Aleppo, his group had recorded 26 dead, including Syrian government soldiers.
Other analysts note that rebel claims of chemical weapons have stemmed from the government's use of incendiary cluster bombs, some of which contain phosphorous and create flames that are difficult to extinguish and smoke that can be particularly harmful when inhaled.