At least 20 people have been killed by gunmen in Iraq, who pulled them out of their cars and shot them "execution style", police say.
This was the third deadline for the ministers to be named
Children, students and elderly men were among those shot dead in the volatile Diyala province, north of Baghdad.
In Basra, at least nine people were killed in clashes between police and Sunni worshippers at a mosque.
The violence comes as a parliamentary session, which was due to vote on three crucial cabinet posts, was postponed.
Deputy parliamentary speaker Khaled al-Attiya announced an indefinite delay amid speculation there was still no agreement on the interior, defence and national security posts.
The BBC's Ian Pannell in Baghdad says the three ministerial posts have a vital role to play in establishing security and have been at the centre of intense political wrangling.
The motorists were killed at a makeshift checkpoint on a road 100km (62 miles) north-east of Baghdad, police said.
AFP news agency reports that seven of the dead were drivers.
In Iraq's second city, Basra, a Sunni religious group accused the police of killing unarmed worshippers at a mosque.
People were pulled from their cars and shot at a makeshift checkpoint
The police said they had come under attack and returned fire, leading to the death of nine "terrorists". AFP says two policemen were also killed.
The police said weapons including mortar shells and hand grenades had been found at the mosque.
On Saturday, at least 28 people were killed in a car bombing in Basra, a mainly Shia city.
Sectarian violence has increased throughout Iraq since the bombing in February of a Shia shrine in the city of Samarra.
The formation of a unity government last month, following months of political deadlock, has raised hopes of ending the violence, but there is still no agreement on the three remaining ministerial posts.
Sunday had been the third deadline given by Prime Minister Nouri Maliki for the ministers to be named.
Sources said Shia parties could not agree on the candidate for the interior ministry.
Hassan al-Sunaid, a member of Mr Maliki's Dawa Party, had earlier named three former military men as those likely to get the nominations.
However, another Shia source said the choices were not so clear cut.
He said Mr Maliki might present two candidates for each post and let parliament vote on them.
Our correspondent says this failure to fill the posts means the chances of being able to deal with security become much more difficult.