A mortar attack in Baghdad killed one person and wounded six others Thursday, in the second attack in Iraq's capital during key talks on Iran's nuclear programme, security and medical officials said.

An interior ministry official said a mortar round struck a street in the Bataween area of central Baghdad, across the Tigris River from the heavily-fortified Green Zone where the talks between Iran and world powers pressing it to scale back its nuclear programme were taking place.

The official put the toll at one dead and six wounded, which was confirmed by a medical source at Ibn al-Nafis hospital.

On Wednesday, the first day of the talks, four people were wounded by a roadside bomb near a Sunni mosque in Al-Yarmuk, west Baghdad.

The attacks come despite heightened security measures in and around the Iraqi capital for the two-day meeting.

Thousands of additional Iraqi security personnel were deployed in areas north, west and south of Baghdad to try to prevent the firing of mortars and rockets into the capital, a security official said.

The official also said without providing figures that additional forces were deployed at checkpoints in the Iraqi capital, and searches increased.

Also on Thursday, a roadside bomb against an army patrol near Dujail, north of Baghdad, killed one soldier and wounded another soldier and three civilians, an army officer said.

And in Mosul in northern Iraq, police on Thursday found the bodies of two girls who had apparently been bludgeoned to death, police First Lieutenant Mohammed Khalaf al-Juburi said.

The two had been kidnapped a day earlier, Juburi said.

Violence in Iraq is down from its peak in 2006 and 2007, but attacks remain common, with 126 people killed in April.