Al Qaida's North African branch blamed Lebanese Shi'ite Muslim militant group Hezbollah for twin bombs that hit the northern city of Tripoli on Friday and threatened retribution, a U.S.-based intelligence monitoring website reported on Saturday. Although al Qaida in the Islamic Maghreb, or AQIM, is not operational in Lebanon, its statement shows a growing regional hatred against Hezbollah by radical Sunni Muslim groups and a wider, deepening sectarian divide in the Middle East. AQIM said in tweets it knew "with certainty" that the Iranian-backed Hezbollah was responsible for the attack that killed more than 42 people in Tripoli.