Nigeria launches assault on Islamists The Nigerian military has launched an all-out assault on Islamist strongholds, officials say. NIGERIA'S military has attacked Boko Haram Islamist strongholds across the northeast, launching air strikes on insurgent camps, with dozens of militants killed in the fighting, the military says. Several thousand soldiers have spread across three northeastern states where President Goodluck Jonathan imposed a state of emergency after Boko Haram seized territory and declared war against the government. Forces have also been deployed to seal some of the region's porous borders and block the insurgents from fleeing, according to residents. "There have been air strikes since Wednesday," defence spokesman Brigadier General Chris Olukolade told AFP, specifying that they were continuing on Friday. "Every one of their strongholds is under attack," he said. "Dozens of the insurgents have likely been killed," he added, without offering a precise figure. The offensive is under way in all three states put under emergency decree, including Adamawa and Yobe, but the extremists' traditional base of Borno state is expected to see the most intense fighting. Many have warned that there is a risk of high civilian deaths and Nigeria's military has been accused of massive rights violations in the past, including indiscriminate attacks on civilians. The operation is the largest against Boko Haram since 2009, when soldiers flooded Borno's capital Maiduguri, killing more than 800 people and forcing the insurgents underground for a year. In the town of Gamburu Ngala on the border with Cameroon in northern Borno, residents said that heavily armed troops and tanks arrived on Wednesday, sealing off previously unmanned border posts. Northeast Nigeria, the epicentre of the Boko Haram insurgency, has porous borders with Cameroon, Chad and Niger, with criminal groups and militants flowing freely between the countries. "Since January the border posts have been abandoned ... but now these posts have been taken over by soldiers," said resident Haruna Garba. Olukolade confirmed that forces had been sent to the region, but would not say whether the borders had been sealed.