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

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.

Pager devices "exploded in the hands of their owners in a number of Lebanese regions" on Tuesday, according to Hezbollah-owned Lebanese media outlet Al-Ahed News. The Lebanese Ministry of Public Health has issued a statement Tuesday instructing all hospitals in various regions of Lebanon to be on maximum alert and raise their level of readiness to meet the rapid need for emergency health services.