The Lebanese militant group Hezbollah fired rockets with heavy warheads at towns in northern Israel, saying it used the weapons against civilian targets for the first time Thursday in retaliation for Israeli airstrikes the night before that killed nine, including what the group said were several paramedics. The Israeli military did not immediately offer comment on the rocket attack. Since the outbreak of the Israel-Hamas war in Gaza on Oct. 7, concerns have grown that near-daily clashes along the border between Israel and Lebanon could escalate into a full-scale war.