The bodies of 14 Sunni Muslim Iraqis have been found shot and dumped in the country's capital, Baghdad.
Dozens of bodies have been found in Baghdad in the past week
The interior ministry is investigating claims from Sunni groups the men were arrested during weekly prayers eight days ago and were not heard from again.
The Association of Muslim Scholars said interior ministry forces had detained the 14 men.
Dozens of other bodies have been found in the past week, in ongoing violence between Sunni and Shia communities.
Maj Gen Hussein Ali Kamal, the ministry's head of intelligence, said the 14 bodies had all been shot multiple times.
But he said he could not confirm whether government forces had detained them.
"We are investigating the residents' reports that these men were arrested in raids in that area but we have nothing so far," he told Associated Press news agency.
The Association of Muslim Scholars says the men were seized as they were while praying at the al-Aqsa Mosque in Shula in north-western Baghdad.
Their bodies were found on Friday evening in the same area, the association said in a statement.
Sunni politician Dr Salman al-Jumaili, a senior member of the Iraqi Islamic Party, accused the interior ministry of conducting "sectarian cleansing" in his community.
Sunni Muslims were the most powerful group in the country under Saddam Hussein, but have since lost much of their power and influence to the Shia Muslims.
A widespread insurgency in predominantly Sunni areas has resulted in many Shia deaths.