A bombing killed three children at a popular swimming area in Iraq on Wednesday after a similar attack two days before, while seven people died in other violence, officials said.

The bomb was planted near Al-Shakha river in the Muqdadiyah area northeast of Baghdad.

The explosion came after mortar rounds struck a swimming area on the Tigris river north of the capital on Monday, killing four people, including a child.

In another attack in the Muqdadiyah area on Wednesday, gunmen opened fire on a car carrying tribal leader Sheikh Majid Ali Jumaili, killing his wife and wounding him, his son and his cousin.

And a roadside bomb killed a policeman and wounded another person to the south of Muqdadiyah.

Areas to the north of Diyala province's capital Baquba, especially Muqdadiyah, have been hit by several attacks in recent days, including a bomb targeting worshippers leaving a Sunni mosque on Tuesday that killed four people and wounded 15.

Parliament speaker Osama al-Nujaifi called for an emergency session of parliament because of the situation in Diyala, especially Muqdadiyah, a statement from his office said.

Armed men also attacked an army checkpoint north of Ramadi, in Anbar province, killing two soldiers, the defence ministry said in a statement.

Three attackers were also killed.

And two bombings in the northern city of Kirkuk wounded two members of the Kurdish peshmerga security forces, a senior officer and a doctor said.

Kirkuk is part of a swathe of northern territory that the autonomous Kurdistan region wants to incorporate over the strong objections of the federal government in Baghdad -- a dispute that officials and diplomats warn is one of the main threats to Iraq's long-term stability.

Wednesday's attacks come as Iraq struggles with its worst violence since 2008.

More than 2,600 people have been killed so far this year, including over 400 so far this month, according to AFP figures based on security and medical sources.