The simultaneous explosion of thousands of pagers used by Lebanese militia Hezbollah on Tuesday was the result of an unprecedented weaponization of a wireless paging system, in which rigged devices detonated upon receiving a coded signal transmitted by radio frequency.

Lebanese officials said that 12 people had been killed on Tuesday, including a young girl. Hezbollah said that at least eight of its fighters were among the day’s dead and more than 2,700 people were injured in Lebanon — including Iran’s ambassador to the country.

Pagers, used every day by health care professionals, became a deadly weapon Tuesday as thousands of them simultaneously exploded in Lebanon.

Explosions went off in Beirut and multiple parts of Lebanon in an apparent second wave of detonations of electronic devices, officials said.

At least 20 people were killed and another 450 were wounded, the Health Ministry said, in this apparent second attack.

For millions of Lebanese, this week's mass explosion of pagers and walkie-talkies, with its bloody aftermath, is painfully similar to the horrific explosion four years ago of haphazardly stored ammonium nitrates that tore through Beirut's port,

Post national security reporter Shane Harris breaks down the Israeli attacks on thousands of Hezbollah pagers and radios on Sept. 17 and 18.

The attacks put the Biden administration in a delicate position as it seeks to avoid a broader war in the Middle East.