Nigeria sect leader defends killings in video
Boko Haram's attacks began small scale - usually drive-by shootings on authority figures or drinking joints in their home town of Maiduguri, in the country's remote northeast corner - but lately have become increasingly sophisticated and ambitious.
In August last year, the sect carried out a suicide car bombing of the United Nations headquarters in the capital Abuja that killed 24 people. On Christmas Day it masterminded coordinated explosions against Christians, including one at a church near Abuja that killed at least 37 people.
The most recent attacks have targeted Christians but dozens of Muslims were killed by the sect last year.
"Anyone who attacks us, we will attack him back even if he is a Muslim. We shall kill anyone who works against Islam, even if he is a Muslim," Shekau said in the online tape.
Gunmen shot dead four people at a petrol station on Wednesday in the northeast Nigerian town of Potiskum, where on Tuesday suspected members of Boko Haram shot dead eight people.
Boko Haram's increasingly violent insurgency has become a major security problem for Jonathan's administration, also facing pressure from nationwide strikes and protests against fuel price increases.
"Four people were shot dead this afternoon but I cannot confirm whether the attackers were Boko Haram," said Tanko Lawal, police commander in Yobe state.
Yobe's government said on Wednesday it has banned the use of motorbikes, which have often been used in Boko Haram attacks, in volatile areas of the state.
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