THE number-plates in Nigeria’s Plateau state declare it to be the “Home of Peace and Tourism”. In the past decade this slogan has sounded ever more fanciful, as the state’s capital, Jos, suffers bouts of the most brutal ethnic violence. The latest took place before dawn on March 7th, when gangs attacked villages south of the city, razed houses and hacked their occupants with machetes. The death toll is hard to know. Aid and human-rights groups say that between 200 and 500 people were killed. The police put the total at 109.

Locals say the gang members belonged to the mainly Muslim Fulani tribe, whereas the villagers were mostly from the Christian Berom group. The killings looked like revenge for a clash in Jos in January, when hundreds died, most of them Muslim, although there were Christian victims too. “This appears to be some kind of reprisal attack,” said Robin Waudo, a spokesman for the Red Cross.

Jos is a tinderbox that sits in Nigeria’s “middle belt”, between the country’s predominantly Muslim north and largely Christian south. The city and its surrounding villages witnessed similar clashes in 2001, which by some accounts left some 1,000 killed, as well as in 2004 and 2008.

Religious differences are just one factor. Africa’s most populous country struggles to contain 150m people and 250-odd ethnic groups. Ethnic division is at the core of tension in Jos; religion adds fuel to the fire. Economic woes make matters worse. The Christian Berom, the majority in this area, resent the economic success of settlers who are mainly Muslim, especially those who buy land. “Those who live here feel they’re being edged out,” says a resident.

The latest attacks will test Goodluck Jonathan, Nigeria’s acting president, who had power thrust on him last month due to the three-month absence of the country’s ailing head of state, Umaru Yar’Adua, in a Saudi clinic. Mr Yar’Adua recently returned but has yet to be seen in public.

Rather reticent as vice-president, Mr Jonathan is becoming more forceful. He put security forces on high alert and sent soldiers to the villages within hours of the attacks. The army was dispatched to Jos after the January clashes. The police say they have arrested some 200 people.

Among other moves, Mr Jonathan has hired a new national security adviser. But this was more about the national power game than the Jos massacre. The acting president’s political base has recently strengthened, though he remains a largely unknown entity. Mr Yar’Adua’s camp is losing ground with each day that he fails to reappear. Abdullahi Sarki Mukhtar, who was sacked by Mr Jonathan as security adviser, was a key ally of Mr Yar’Adua.

There is scepticism in Jos that the authorities will bring a lasting peace. A curfew has been in force for more than a year. Those arrested after previous clashes have rarely been convicted. A probe set up by Mr Yar’Adua into the killings of 2008 failed to have any serious effect, as did earlier inquiries. Many residents say that local politicians stir ethnic and religious feelings to win votes. “They align themselves with people to get what they want,” says Patience Dassah at the League for Human Rights in Jos.