BAGHDAD — Iraq’s Christian community was in shock Monday after Islamist militants in suicide vests besieged a church during Sunday Mass and then fought Iraqi commandos in a melee that left at least 58 people dead.

Officials said that in addition to the priests, worshipers and security forces killed, 75 more people were injured after Iraqi special forces stormed Our Lady of Salvation Syriac Catholic Church where gunmen were holding the congregation.

Church leaders blamed inadequate security by the Iraqi government for the deadliest attack in Baghdad since before March elections.

“If the sons of this country cannot live in peace, then the situation is clearly unacceptable. Had we been provided with adequate security, this would not have happened,” Syriac church official Monsignor Pius Kasha told McClatchy Newspapers.

As an elite commando unit under control of Prime Minister Nouri al-Maliki’s office stormed the church Sunday night after a four-hour standoff, gunfire and explosions rocked central Baghdad. Witnesses and survivors say the attack started with a team of insurgents dressed in military uniforms killing guards at the nearby Baghdad stock exchange before they scaled the walls and started shooting inside the church.

The dead included two young Iraqi priests and a church deacon, as well as families attending Sunday Mass at the church in the central Karrada neighborhood of Baghdad, church officials said.

The Iraqi federal police and army have been deployed outside churches during Sunday Mass since a series of coordinated attacks on churches more than two years ago. On Sunday though, witnesses said there were no military or police vehicles deployed outside the church during the service.

Nearby residents described terrifying scenes unfolding into the night. Rajaa, a school teacher who did not want her last name used, said that from the first-floor window she saw four men in military uniforms get out of a black SUV and shoot at the stock exchange guards before jumping the wall into the church.

An Iraqi television station said it had received a call from the Islamic State of Iraq, an al-Qaida-affiliated group, claiming responsibility for the attack and saying they were demanding the release of prisoners in Iraq and Egypt.

Most of the casualties were thought to have resulted after the gunmen detonated two suicide vests when Iraqi commandos blew off the doors and stormed the building.

“The men who carried out the attack were very organized — the way they entered, how well-prepared and armed with machine guns, explosive belts and everything they could need. … How they quickly closed the doors and shut in the faithful. Then the security forces came and it was a real tragedy; so many lives lost,” Kasha said.

Iraqi authorities and the U.S. military publicly praised the rescue attempt, even though more than half of the parishioners were killed or seriously wounded. Defense Minister Abdulqadir al-Ubaidi said the insurgents included foreign fighters who intended to kill as many people as possible.

A U.S. military spokesman said the U.S. role was limited only to providing an aerial surveillance feed for the operation, but witnesses said a small group of U.S. soldiers were on the ground.