A barrage of car-bomb blasts and suicide bombings rocked Baghdad and two northern Iraqi communities on Thursday, killing at least 61 people, Iraqi authorities said. The bulk of the blasts struck in mainly Shiite parts of Baghdad shortly after nightfall. The authorities reported nine car bomb explosions across Baghdad, including one near a playground that killed two children. In addition to the bombings in the capital, explosives were set off north of Baghdad, near Mosul and in Tuz Khurmato. The attackers struck as Muslims were observing the religious holiday of Id al-Adha, or the Feast of Sacrifice. Iraq’s resurgent branch of Al Qaeda is believed to be behind much of the recent outburst of killing as part of its campaign to undermine the Shiite-led government.