The United States, European Union and almost a dozen other countries called jointly on Wednesday for an immediate 21-day ceasefire to allow for negotiations between Israel and Hezbollah amid fears that the escalating conflict could plunge the broader region into an all-out war.

Israel and Hezbollah, which is based in Lebanon and backs fellow Iranian proxy group Hamas in its ongoing war with Israel, have been engaged in cross-border attacks since Hamas’s Oct. 7 terrorist attack on Israel, in…