Here's the Post's Joel Greenberg reporting from Jerusalem on Israel's minor but startling volley in a conflict it has seemed to assiduously avoid entering:

The Israeli army said Monday that it had targeted and hit a Syrian mobile artillery battery after an errant mortar shell fired during fighting between Syrian troops and rebels landed near an army post in the Israeli-held Golan Heights.

It was the first time Israeli forces had engaged Syrian troops across the Golan frontier since the 1973 Middle East war, and it came a day after the army fired a guided anti-tank missile into Syria as a warning after another stray mortar round hit a military post.

The renewed fire on Monday further heightened concerns that the Syrian conflict could draw in Israeli forces stationed in the Golan Heights, a strategic plateau taken by Israel from Syria in the 1967 Six-Day war. The cease-fire line in the Golan, where Israeli and Syrian troops are separated under terms of a disengagement agreement, has been quiet for decades.

Israel is deeply ambivalent about the conflict and not eager to take sides, former Israeli ambassador to the United States Itamar Rabinovich tells Foreign Policy's David Kenner. Rabinovich, who also served as Israel's negotiator with Syria during the 1990s, explained, "When you don't have great choices, you don't really push hard for any of them."