Deadly Israeli attacks that blew up Hezbollah radios and pagers crossed all red lines, the leader of the heavily armed Iran-backed Lebanese movement said on Thursday, as the United States called for restraint and urgent de-escalation.

At least 12 people were killed, including an 11-year-old boy and a 9-year-old girl, and more than 2,700 people injured in the coordinated explosions of pagers that belonged to Hezbollah members. A day later,

Israel has responded to Hezbollah’s fire with strikes in southern Lebanon, and has struck senior figures from the group in the capital Beirut. The exchanges have killed hundreds in Lebanon and dozens in Israel and forced the evacuation of tens of thousands of residents on each side of the border.