Three suicide bombings claimed by the so-called Islamic State across Baghdad killed at least 86 people today, in the deadliest attacks in the Iraqi capital this year.

Security has gradually improved in Baghdad, which was the target of daily bombings a decade ago, but violence against security forces and Shia Muslim civilians is still frequent.

Large blasts sometimes set off reprisal attacks against the minority Sunni community.

The fight against Islamic State, which seized about a third of Iraq's territory in 2014, has exacerbated a long-running sectarian conflict in Iraq mostly between Sunnis and the Shia majority that came to power after the US-led invasion in 2003.

Such violence threatens to undermine US-backed efforts to defeat the militant group.

Today’s bombings could also intensify pressure on Prime Minister Haider al-Abadi to resolve a political crisis that has crippled the government for more than a month.

The first attack, a suicide car bomb at a bustling market in the Shi'ite Muslim area of Sadr City, killed at least 64 people during morning rush hour and wounded 68.

Two more blasts struck at the end of the working day.

A suicide bomber stormed a security checkpoint, killing 17 and wounding more than 30.

Another bomb went off at a checkpoint on a commercial thoroughfare in a predominantly Sunni district of western Baghdad, killing eight and wounding 20.

Brides and grooms 

The first blast today was from a pickup truck packed with explosives which went off in the Sadr City area near a beauty salon in a bustling market at around 10am (8am Irish time).

Many of the victims were women including several brides who appeared to be getting ready for their weddings, sources said.

The bodies of two men said to be grooms were found in an adjacent barber shop.

Smoke was still rising from several shops hours after the explosion as a bulldozer cleared the burnt-out chassis of the vehicle used in the blast.

Islamic State said in statements circulated online by supporters that a car bomb had aimed at Shia militia fighters gathered in the area and two fighters wearing explosive vests targeted security forces in the later attacks.

Since 2014, Iraqi forces backed by US-led air strikes have driven the group back in the western province of Anbar and are preparing for an offensive to retake the northern city of Mosul.

A spokesman said today that Islamic State had lost two-thirds of the territory seized by the militants in 2014.

Yet the militants are still able to strike outside territory they control.

The ultra-hardline Sunni jihadist group, which considers Shia apostates, has claimed recent attacks across the country as well as a twin suicide bombing in Sadr City in February that killed 70 people.