Updated

A police officer arguing with a merchant was stabbed to death in a market and at least two others were killed during the latest violence to hit a central Nigerian region beset by sectarian fighting, officials said Wednesday.

The violence in a small market in Jos erupted as Muslims observed the birthday anniversary of Islam's prophet Mohammed. Officials, though, said the fighting Tuesday was not related to the religious tensions in the region.

Authorities said an off-duty policeman was arguing with a man selling him chicken when the officer was stabbed in the stomach. Officials believe two other killings at the market were caused by hoodlums who took advantage of the commotion.

"The stabbing of the officer caused pandemonium," Brigadier Hassan Umaru, an army commander, said Wednesday, adding that seven others were wounded. "People were running in different directions."

Jos has been a flashpoint for a series of conflicts ever since 2001 riots killed more than 1,000 people. Muslim-Christian battles killed up to 700 people in 2004 and more than 300 residents died during a similar uprising in 2008. Human Rights Watch says at least 1,000 people were killed in Jos in 2010 and another 200 more have died since Dec. 24.

Nigeria, an oil-rich country of 150 million people, is almost evenly split between Muslims in the north and the predominantly Christian south. Jos is in the nation's "middle belt," where dozens of ethnic groups vie for control of fertile lands. The Jos violence, though fractured across religious lines, often has more to do with local politics, economics and rights to grazing lands.