The attack on the militant group has prompted several investigations into the supply chain behind the devices that detonated this week.

Lebanon's Hezbollah was still handing its members new Gold Apollo branded pagers hours before thousands blew up this week, two security sources said, indicating the group was confident the devices were safe despite an ongoing sweep of electronic kit to identify threats.

The blasts took place in several suburbs of Beirut, according to Lebanon's National News Agency. The cause of the explosions was not clear.

The pager and walkie-talkie attacks were extremely sophisticated in their planning. But the strategic goal isn't clear.