BEIRUT, Lebanon (AP) — Israel struck Lebanon on Saturday in retaliation for rockets targeting Israel, killing two, including a child, in the heaviest exchange of fire since the ceasefire with the Lebanese militant group Hezbollah.

Earlier, rockets were fired from Lebanon into Israel, for the second time since December, sparking concern about whether the fragile ceasefire would hold. A Hezbollah official told The Associated Press Saturday that it was not responsible for the attack, calling it “primitive,” speaking on condition of anonymity as they are not authorized to speak to the media.