Israel's Mossad spy agency planted explosives inside 5,000 pagers imported by Lebanese group Hezbollah months before Tuesday's detonations, a senior Lebanese security source and another source told Reuters.

Israeli Defense Minister Yoav Gallant did say on Wednesday, however, that his country's war with Iran's so-called proxy groups in the region had entered a "new phase," announcing a shift to the north of Israel after 11 months of intense conflict with Hamas in the Gaza Strip.

Thousands of pagers used members of the militant group Hezbollah exploded near simultaneously in Lebanon and Syria, killing at least nine people and wounding several thousand, officials said.