COLOMBO, Sri Lanka — The clock hands on the steeple of St. Anthony’s Shrine were stuck at 8:45 a.m., the exact moment when the first suicide bomber’s explosion ripped through the wooden pews as Easter Sunday worshipers were praying.

Minutes later a second suicide blast shattered the Sunday brunch tranquillity at the Shangri-La Hotel’s Table One Restaurant, a favorite of foreign tourists.

Within a few hours on Sunday, suicide bombings hit three Christian churches and three upscale hotels in the Indian Ocean island nation of Sri Lanka, still recovering from a quarter-century civil war in which the suicide bomb was pioneered.

The death toll in the attacks rose to 290, with about 500 people wounded, a police spokesman, Ruwan Gunasekera, said, although he would not give a breakdown of where the fatalities occurred. The finance minister, Mangala Samaraweera, called the attacks “a well-coordinated attempt to create murder, mayhem and anarchy.”

By day’s end, the police said at least 13 people had been arrested in connection with the attacks in the capital, Colombo, and the cities of Negombo and Batticaloa. Seven of them were seized at a hide-out after one suspect blew himself up, killing three officers.