A series of bomb attacks in the north-eastern Nigerian city of Damaturu has killed at least 30 people, reports say.Witnesses said the bombs hit several targets, including the headquarters of the Yobe state police.The BBC's Jonah Fisher, in Nigeria's commercial capital, Lagos, says gunfire lasted into the night and residents were said to be fleeing.It follows attacks on security forces in the nearby city of Maiduguri blamed on the Islamist Boko Haram group.Our correspondent says there are reports that as many as 60 people have been killed in Damaturu.The state police commissioner said the attacks caught the town by surprise.