Two suicide bombers detonated explosive vests at on Baghdad's busy Tayran Square at rush hour on Monday, killing at least 31 people and wounding more than 60 others.

There was no immediate claim of responsibility, but Prime Minister Haider al-Abadi referred to "IS sleeper cells," who he said must be "eliminated."

The bombings came two days after a suicide bomber had struck a police checkpoint in northern Baghdad, killing eight people.

Read more: The legacy of the "Islamic State"

In December, Abadi had declared victory over Islamic State (IS), which the militia evicted last year from Mosul and other swathes of northern and western Iraq.

Monday's attack shocked Baghdad residents after a decline in such violence in months. Analysts had warned, however, that IS would turn to such tactics as elections due in May approach.

The insurgents aimed to "create chaos and exacerbate sectarian divisions," said Iraqi analyst Hisham al-Hashemi.

Read more: Iraqi PM Haidar al-Abadi announces bid for re-election

Survivor, Munthir Falah, a vendor of secondhand clothes and father of three blamed government forces for not doing enough to secure the capital and its residents.

"They think that Daesh (Arabic name for IS) is done with the territorial loses and they [government security forces] do not bother themselves to exert efforts to secure Baghdad," he said.

Iraqi parliamentary speaker Salim al-Jabouri denounced the attack as a "cowardly act against innocent people" and called on the government to take all necessary security measures.

ipj,cw/ng (AFP, AP, dpa, Reuters)