The bloc aims at unifying Sunni Arabs and organising their participation in the country's future political process.
Head of the Waqf al-Sunni (Sunni Endowments) Adnan al-Dulaymi said Sunni Arabs had a duty to participate in the coming political process, namely the writing of a constitution.
"Arab Sunnis will participate in the political process to maintain the Iraqi identity and to prevent marginalising Sunnis or degrading them," he added.
The new Sunni group's first act was to demand that the interior minister resign.
Calling for resignation
A statement issued after about 1000 representatives of the disempowered community, gathered in Baghdad, accused Interior Minister Bayan Jabr - a member of the Shia community - of being responsible for the assassination of several Sunnis, including three imams.
Bayan Jabr (R): We did not
practise killing against anyone
"We ask for the creation of an independent investigation team to look into the murders, the torture of detainees and we demand the interior minister's dismissal," the statement said.
"We condemn the raids and arrests of imams and worshippers in mosques under the cover of law," the statement added.
But Jabr lashed back saying: "No one has the right to call for the resignation of a minister, only parliament can do that. Those who didn't get one vote have no right to ask," he said, referring to the fact that many Sunnis stayed away from 30 January elections either in protest or for fear of attacks.
"We did not practise killing against anyone," he added.
The formation of the Sunni bloc, however, did little to quell violence in the country.
Twelve soldiers from the Iraqi Interior Ministry's elite commando unit were killed in a string of attacks in towns north of Baghdad on Saturday, security sources said.
Four commandos and a civilian were killed in a bomb attack in Samarra, 125km north of the capital, police said.
Sunni mosques remained closed
"Two more commandos were killed in a rocket attack on a police station in the city centre moments later," the same source said.
In Baiji, further north, six other members of the commando battalion al-Raad (Thunder) were shot dead in intense fighting that broke out in the key oil refinery town's industrial zone, police Colonel Saad Nufus said.
Meanwhile, Sunni imams continued their closure of mosques in a three-day shutdown to protest against the murder of members of their community.
From the minarets of Baghdad, Sunni muezzins on Saturday issued their five-times-a-day call to prayer, but added: "Remain where you are to say your prayers" as the mosques remained closed to protest at recent unexplained murders of civilians and clerics that some Sunni Arab leaders have blamed on a Shia militia with links to the government.