TEL AVIV, Israel — A senior Israeli Air Force officer on Monday provided operational context to the unusual March 17 Arrow intercept of a Syrian SA-5 surface-to-air missile, which the jointly developed U.S.-Israel anti-ballistic missile system was not designed to fight.

Briefing reporters here, the officer said the Syrian SAM launched against Israeli fighter aircraft following a bombing mission in Syria "behaved like a ballistic threat" with "an altitude, range and ballistic trajectory" that mimicked the Scud-class targets the Arrow 2 interceptor was designed to kill.

"It wasn't a Scud-class ballistic threat. But from our perspective, it doesn't matter if it was a SAM. Once it behaved like a ballistic missile weighing tons and with a warhead of hundreds of kilograms, we couldn't allow it to threaten our cities and towns," the officer said.

When asked to identify the specific threat, the officer confirmed that the Arrow 2 had indeed scored its first operational intercept against a Syrian SA-5.

"In this case, it behaved just like a ballistic missile," he added.

Another military officer later explained that in the aftermath of the March 17 attack, Syria launched several SA-5s in a southwestern direction toward Israel as Israeli F-15Is were returning home from "a successful strike mission against high-value assets" destined for Hezbollah arsenals across the border in Lebanon.

Contrary to criticism leveled over the weekend by former Israeli Prime Minister and Defense Minister Ehud Barak, who suggested that Israel should not have launched Arrow in order to preserve the country’s longstanding policy of ambiguity regarding periodic strike operations in Syria, the senior Israeli Air Force officer said Israeli air defenders didn’t think twice about acting against the approaching threat.

"No doubt about it, our mission is to detect and engage this threat, and that’s exactly what we did Friday morning. The mission of our air defense forces, under my responsibility, is to defend the people of Israel. And that was the case last week when Syria launched a missile that was seen as a ballistic threat to Israel," the officer said.

Experts on Friday had surmised that since Arrow was not designed to intercept SAMs, and since such anti-air missiles are not part of the system’s database that automatically tracks trajectories and predicts impact points of incoming ballistic missiles, that the target of the early morning March 17 interception could have been a Scud-class missile.

Based on scant information available at the time, experts wondered why Israel would launch Arrow against a SAM that ostensibly should have posed no threat to the homeland, given that it aimed to shoot down Israeli fighters operating hundreds of kilometers away. They noted that the SA-5 is designed to either hit enemy aircraft or self-explode after a few seconds of engine burn, rather than proceed flying intact along a flight profile that matches that of Scud-class targets.

But given the officer’s explanation, one expert here noted that the Syrian-launched SA-5 could have been very old, and thus did not self-destruct as designed.

"It should have destroyed itself. But it’s an old missile and it probably remained in one piece. And in that case, if it didn’t self-destruct after a certain time, all the weight was in the front and it represented a stable body, large wings and a tail … all the characteristics of a ballistic missile trajectory," said Uzi Rubin, a former director of Israel Missile Defense Organization.

"Now it all makes perfect sense. … Apparently the software of the Arrow system is such that is flexible enough to cope with unexpected situations," he added.

"It’s an impressive achievement for which we all should be very proud."

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