BAGHDAD — As Sunni militants rampaged across northern Iraq last week, executing Iraqi soldiers and government workers and threatening to demolish Shiism’s most sacred shrines, Iraq’s Shiites suffered mostly in silence, maintaining a patience urged on them by their religious leaders through months of deadly bombings.

On Tuesday, though, there were signs that their patience had run out.

The bodies of 44 Sunni prisoners were found in a government-controlled police station in Baquba, about 40 miles north of Baghdad. They had all been shot Monday night in the head or chest. Then the remains of four young men who had been shot were found dumped Tuesday on a street in a Baghdad neighborhood controlled by Shiite militiamen.

By evening, it was Shiites who were the victims again, as a suicide bombing in a crowded market in Sadr City killed at least 14 people, local hospital officials said.