A suicide attack claimed by the Islamic State group killed at least eight people at a Shiite mosque on the southwestern edge of Baghdad on Friday, security and medical officials said.

The blast, which occurred shortly after Friday prayers, also wounded at least 33 people, the officials said.

An AFP journalist saw the bodies of three people being taken away in coffins from the site of the attack.

Gunmen wearing military uniforms with patches identifying them as members of the Asaib Ahl al-Haq militia surrounded the site of the bombing and prevented media from taking photographs or video, the journalist said.

The Islamic State group issued a statement claiming the attack, saying it was carried out by two militants.

An interior ministry official also said that two suicide bombers were involved, but a police colonel put their number at one.

IS carries out frequent bombings and other attacks targeting members of Iraq's Shiite majority, whom it considers heretics.

IS overran swathes of territory north and west of Baghdad in 2014, but Iraqi forces backed by US-led air strikes have since regained significant ground.

Bombings in Baghdad have decreased since mid-2014, with the jihadists preoccupied by fighting in other areas.

But IS still controls a large part of the country's west, and is able to carry out frequent bombings in government-held areas.