The death toll from ongoing sectarian clashes in northwest Pakistan has risen to at least 37, with more than 150 injured in fighting that has raged for a sixth straight day, a local official told AFP on Friday. The Kurram district, formerly a semi-autonomous area, has a history of bloody confrontations between tribes belonging to the Sunni and Shia sects of Islam that have claimed hundreds of lives over the years. July clashes over land involving the same tribes killed 35 people and ended only after a jirga (tribal council) called a ceasefire, with officials attempting to broker a new truce. F…