Three members of Iraq's main Sunni Arab political party have been abducted and killed in the northern city of Mosul.
The three men were seized as they hung posters urging people to vote
The Iraqi Islamic Party members were seized as they put up posters urging Sunnis to vote in a referendum planned later this year on a new constitution.
Politicians are still wrangling over the draft constitution, ahead of an extended deadline to present it to parliament for approval.
Meanwhile, two Iraqis were reported killed by a roadside bomb near Tikrit.
A spokesman for the Iraqi Islamic Party, Noureddine Hayali, said the three men had been kidnapped early on Friday in a southern neighbourhood of Mosul.
They were then driven to another part of the city before being shot dead in front of a mosque, Mr Hayali said.
The killings came a day after an attack in Ramadi on Sunni leaders who had been discussing voter registration, in which several people were injured.
The BBC's Barbara Miller says Iraqi politicians have expressed optimism they can reach a deal on the draft constitution before the extended deadline of 22 August.
But the latest violence could further delay agreement, she warns.
The constitution needs to be approved by the National Assembly before it can go to a nationwide referendum in October.