The armed group Islamic State of Iraq and the Levant has claimed responsibility for a suicide bombing in central Baghdad that police said killed seven people and wounded 27.

The blast occurred on Tuesday near a gathering of workers in Tayaran Square, about a kilometre from a sit-in held by supporters of influential Shia cleric Moqtada al-Sadr to demand political reforms.

ISIL (also known as ISIS), which claimed responsibility in an online statement, also said it was behind a suicide bombing last Friday that killed 26 people at an amateur football game in Iskandariya, south of Baghdad.

Phone camera captures suicide bombing in Iraq stadium

At least 60 people were also killed earlier this month in an attack further south in Hilla when an explosives-laden fuel tanker slammed into an Iraqi security checkpoint.

Some analysts say the escalation of bombings targeting areas outside ISIL's primary control in northern and western Iraq suggests that Iraqi forces may be stretched thin after recent gains against the armed group.

Analysts in Europe have interpreted recent attacks there, such as last week's bombings in Brussels or the killings in Paris last November, as a sign that ISIL is expanding its field of action in response to setbacks in Iraq and Syria, where it governs a self-styled Islamic caliphate. 

But Baghdad analysts said the group has long staged indiscriminate suicide bombings and see these attacks as a continuation of that tactic.

Meanwhile,  the Combined Joint Task Force against ISIL said on Tuesday that the United States and its allies conducted four air strikes against ISIL on Monday.

A statement said four strikes near three cities in Iraq hit a bed-down location and a safe house, destroyed five assembly areas, and suppressed a machine gun position.

Elsewhere in Fallujah, Iraqi army shelling targeting ISIL hideouts killed four people, including two children. At least nine people, mainly women and children, were also wounded.

About 400 ISIL fighters are still in Fallujah, which fell to the armed group more than two years ago.

Source: Agencies