Below is an article published by Al Jazeera:

An al-Qaeda-linked group has claimed responsibility for an attack on a Catholic church in the Iraqi capital, which resulted in the deaths of at least 37 people, including 25 hostages.

Attackers stormed the Our Lady of Salvation church in the Karrada neighbourhood of central Baghdad on Sunday night, taking more than 100 people hostage. The standoff was ended after police stormed the church two hours later.

Seven members of the security forces and five gunmen were amongst those killed.

"Right from the very beginning their phone calls were fully intercepted and we strongly believe there were non-Iraqi people among the group. We will investigate their nationalities," Abdul Qader al-Obeidi, the Iraqi defence minister, said.

The Islamic State of Iraq, a group which is linked to al-Qaeda, has claimed responsibility for the attack.  The attackers were demanding the release of female prisoners from Iraqi and Egyptian jails, Al Jazeera's Stefanie Dekker reported.

Major-General Qassim al-Moussawi, a Baghdad security spokesman, told the Reuters news agency on Sunday that the operation "has finished successfully".

Sunday's attack began with at least one loud explosion followed by bursts of gunfire. Streets around the church were quickly cordoned off.

Earlier the assailants, wearing suicide vests, killed two guards who tried to stop them from raiding the stock exchange building.

After battling security forces at the stock exchange, the men fled to the nearby church, where they held the building's construction and cleaning crew hostage inside.

Abdullah Hermiz, the head of Christian Endowment, a state body that oversees Iraq's chruches, told The Associated Press news agency that only part of the building was under construction and that Sunday services were being held as usual in another part of the church.

"When they were about to leave and heard the shooting outside and because of the scary situation, some ran outside the church while others remained inside," he added.

Al Jazeera's Rawya Rageh, reporting from Baghdad, said that according to the US military the attackers were al-Qaeda operatives, based on their "tactics, techniques and procedures".

Lieutenant-Colonel Eric Bloom, a US army spokesman, said about 100 people had been in the church when the attackers came in, but some 19 of them managed to escape.

"They [Iraqi forces] went into the church and rescued the hostages," Bloom said. "They have control of the church".

He said US forces provided air support but did not have soldiers on the ground going into the church. Iraqi Special Forces stormed the church around 9 pm.

Bloom later told Al Jazeera that the incident was a "robbery gone wrong".

"We've seen them resort to robbery to get financed. It has been very challenging for them to get outside financing, so they are resorting to small, petty crimes to try to finance themselves".

Al-Baghdadiya television station said it had received a phone call from someone claiming to be one of the attackers, who demanded the release of all al-Qaeda prisoners in Iraq and Egypt.