Israel said on Thursday that its ceasefire with Hezbollah was breached hours after Lebanese security sources said Israeli tanks attacked six areas of southern Lebanon, calling into question a truce reached after more than a year of fighting.

In what might be his final achievement as president, Joe Biden, his diplomats, and their French counterparts have brokered a ceasefire in the increasingly brutal yearlong war between Israel and Hezbollah’s Islamist militia in Lebanon.