The absence of a full-blown war in Lebanon has been touted as a core U.S. achievement, but now Washington’s grip on the crisis appears more tenuous than ever.

Daily exchanges of fire between Hezbollah and Israel have been destructive, disruptive and sometimes deadly. An escalation could risk starting a wider regional conflict.

The Israeli military said it was striking Hezbollah targets in Lebanon on Thursday, shortly before the movement's leader was due to give a speech. It also said the military chief of staff had approved plans for Israel's north,