The militant Islamist group Boko Haram is believed to be behind a series of explosions that demolished 24 mobile phone masts in Nigeria.
A military spokesman blamed the violent jihadist organisation for the attacks on nine mobile phone companies in the cities of Kano, Maiduguri, Potiskum, Gombe and Bauchi.
The group has not claimed responsibility but had earlier threatened the companies after accusing them of helping security agencies monitor members.
The damage runs into millions of pounds. A single tower costs more than $1m (£627,000).
Among the companies attacked were South African telecom giant MTN and United Arab Emirates firm Etisalat.
"We confirm that like all the other major telecoms, some of MTN's installations in northern Nigeria have been damaged by unknown persons," a spokeswoman said.
The latest bombing campaign was a new tactic by Boko Haram. Since 2009 they have carried out armed attacks on churches, government buildings and media outlets across the county in their fight to turn Nigeria into a Muslim country under sharia law.
In August, the personal data of more than 60 Nigerian secret service agents including home addresses and names of immediate family, were dumped online by the militants.
The north of Nigeria is predominantly Muslim, while Christianity and animism are the main religions in the south.