The Hezbollah militant group said it is conducting a "security and scientific investigation” into the explosion of pagers across Lebanon on Tuesday.

This week's explosions have also deepened concerns about the scope of potentially compromised devices, particularly after such bombings have killed or injured so many civilians. Here's what we know so far.

Thousands of pagers and radios held by Hezbollah members have exploded across Lebanon and Syria, killing more than a dozen people and wounding thousands. The attacks bear the hallmarks of Israel's Mossad intelligence agency,

Israeli public broadcaster Kan said on Friday around 150 rockets were fired from Lebanon across the border. Israeli ambulance service said there were no immediate reports of casualties. Lebanon's Hezbollah announced on Friday they launched seven separate attacks on Israeli targets with Katyusha rockets.

Walkie-talkies and solar equipment exploded in Beirut and other parts of Lebanon on Wednesday in an apparent second wave of attacks targeting devices a day after pagers used by Hezbollah blew up, state media and officials for the militant group said.