(CNN) -- There are ominous signs in Nigeria that the campaign of violence by the militant Islamist group Boko Haram is leading to wider and more explosive sectarian tensions -- in a country where Christian-Muslim relations are often tense and sometimes bloody.
The last two months have seen widespread bloodshed in northern Nigeria, with churches and police stations among the targets.
Boko Haram (which according to the group means "Western civilization is forbidden") has claimed responsibility for a series of attacks on churches in central and northern Nigeria on Christmas Day, including one near the capital, Abuja, which killed nearly 30 people.
Two days later, a bomb attack at an Islamic school -- or madrassa -- in the southern Delta state injured several children. It's not clear whether it was intended as revenge, but such sectarian attacks are rare in Delta state.
Nigerian President Goodluck Jonathan called a meeting of military and police chiefs on Thursday to review the deteriorating situation. National police chief Hafiz Ringim was quoted by local media afterward as saying, "We are all scrambling to find our feet and face [the threat] squarely."
Boko Haram demands the imposition of Islamic Sharia law across Nigeria, and has recently extended its attacks beyond the deserts of northern Nigeria.
One of the Christmas bombings took place in Jos, long a fault line in Nigeria's sectarian divide.
Christian leaders have demanded a stronger response to the attacks from the government and the Muslim community. Ayo Oritsejafor, head of the Christian Association of Nigeria, complained Wednesday that the response of Islamic leaders had been "unacceptable and an abdication of their responsibilities."
"The Christian community is fast losing confidence in government's ability to protect our rights," Oritsejafor said.
David Cook of Rice University, who has studied the rise of Boko Haram, says that "if radical Muslim violence on a systematic level were to take hold in Nigeria...it could eventually drive the country into a civil war."
Shehu Sani, a human rights activist based in northern Nigeria, shares that fear. Sani, who has tried to mediate between Boko Haram and the government earlier this year, warns that Christian retaliation "would be unimaginable in a nation racked by deep divisions."
Corruption, poverty and a lack of government services have helped Boko Haram gain support, especially among young Muslims out of work. So has a perception that the Muslim north has been marginalized by a political establishment drawn largely from the Christian south.
Boko Haram dramatically expanded its campaign of terror after its leader, Mohamed Yusuf, was shot dead while in police detention in July 2009. Just over a year later, the group attacked a prison, freeing more than 700 prisoners, including 100 of its own members.
Cook says that since then the group has been responsible for at least 45 major operations, which have included assassinations -- frequently using gunmen on motorbikes -- and more recently suicide bombings beyond its northern heartland.
Beyond the security forces and Christian targets, it has assassinated Muslim clerics who oppose the group -- and even killed a prominent Boko Haram member who had attended talks to explore a truce. Boko Haram's presence in the city of Maiduguri has made it almost ungovernable, according to analysts.
Its ability to inflict mass casualties has grown fast. In August, a suicide bomber struck the U.N. building in Abuja, killing 23 people. In November, some 150 people were killed in a series of bombings and shootings in Damaturu, capital of Yobe state. In a just-published paper for the James Baker Institute for Public Policy, David Cook says "Boko Haram went through the Christian quarter of Damaturu and massacred anybody who did not know the Muslim creed."
More recently, clashes between security forces and Boko Haram in Damaturu have led some 90,000 people to flee their homes, according to state officials.
The former U.S. ambassador in Nigeria, John Campbell, argues on his blog that Boko Haram "may be intent on showing Nigerians and the international community that it can make the country ungovernable for President Goodluck Jonathan's predominantly southern Christian administration."
But Campbell and others argue that Boko Haram has not yet shown it can operate in wide swaths of Nigeria's Muslim heartland, nor the commercial capital, Lagos.
The commander of U.S. Africa Command, Gen. Carter Ham, has suggested Boko Haram may have developed links with other Islamic jihadist groups in the region, especially al Qaeda in the Islamic Maghreb.
But Campbell believes Boko Haram is "financing itself through bank robberies and is arming itself by thefts from government armories and purchases -- there is no shortage of weapons on the market."
Less than two months ago, Jonathan described attacks by Boko Haram as a temporary setback, which would soon be a thing of the past. Now he appears to see the group as a lethal threat that demands the full attention of the security services.
But since Yusuf's death, Boko Haram has had no obvious leader or structure and appears to act as loosely connected cells. And it is feeding on deep-seated grievances which the government seems unable to address.
David Cook warns that "as more and more territories become ungovernable, such as Maiduguri, then Muslims more and more will want to join Boko Haram, if only because it represents the one group that can actually project power and hold out the illusion of security to the people."