MAIDUGURI, Nigeria (AP) — A radical Islamist sect that has attacked mosques, churches, schools and government buildings at will in Nigeria appears to have added a new target for its violence: mobile phone towers.

Attacks in the last day have damaged more than 30 towers operated by all the major providers in the country, further straining the one link the nation relies on for communication in a country with nearly no landlines. While no one has claimed responsibility for the attacks, the Islamist sect known as Boko Haram threatened mobile phone companies six months ago, warning that they would be targeted for cooperating with the government to flush out its members.

The assaults, which continued into yesterday morning, appear to be "an attack on the telecoms industry," said Gbenga Adebayo, the chairman of the Association of Licensed Telecommunications Operators of Nigeria. It also would be a further strain on people living in a region long under attack by the radical sect.

"We are worried because this infrastructure is meant to serve the public," Adebayo told The Associated Press. "So an attack on infrastructure is an attack on the public itself."

Communications across northeast Nigeria remained difficult yesterday, with residents unable to connect calls or having them drop in mid-conversation. Internet service also was poor, as most access the web through mobile phone networks. It could take months for service to improve in the region, especially if attacks continue as other companies have been leery of sending staff to the region.

In Nigeria, home to more than 160 million people, mobile phones serve as a valuable lifeline across both cities and rural communities. Landlines remain almost nonexistent, as the state-run telephone company has collapsed and repeated efforts to privatise it have failed. More 87 million mobile phone lines were in use in 2009, according to estimates.

A survey yesterday by AP journalists across northern Nigeria found at least 31 attacks occurred in six states, spread from the central state of Kano to the far eastern state of Borno. In Maiduguri, the capital of Borno state where Boko Haram began, an AP journalist saw and received information about 13 burned mobile towers. The journalist also saw the burned remains of what used to be the city's main office for South Africa-based MTN Group Ltd, Nigeria's largest cell network provider.

MTN acknowledged in a statement yesterday that "attacks have been made on some of its installations in northern Nigeria by unknown persons" and that customers may experience outright network failure following the attacks. Typically, a mobile phone will continue to seek a signal at another nearby tower, meaning networks can quickly be overloaded if towers go offline.

"We are intensifying efforts to restore normal services as soon as possible," MTN executive Akinwale Goodluck said in the statement.

Officials with Bharti Airtel of India, Abu Dhabi-based Etisalat and local firm Globacom Ltd, the nation's other major telecommunication firms, could not be immediately reached for comment yesterday. However, Adebayo said the attacks affected all four companies and five others.

In neighbouring Adamawa state, attackers set ablaze five towers in the town of Mubi, Adamawa state police spokesman Ibrahim Muhammad said. He said that two civilians were shot dead in the late night attacks. An AP journalist also saw two burned masts in Kano, the capital of Kano state.