"Twenty-seven terrorists were hanged today in Baghdad. Most of them were Iraqis," interior ministry spokesman Abdul Karim Khalaf said.
He said they were convicted for attacks on civilians and sentenced to death, in an execution order signed by an Iraqi vice president.
Meanwhile, six Iraqis were killed and 46 more wounded in a pair of bombings at a bus stop in Baghdad during the morning rush-hour.
Later, a suicide bomber killed five Iraqis and wounded 18 others when he detonated an explosive-laden car near a police fuel depot in Baghdad's Karrada district, a security official and medics said. Three of the dead were policemen.
In another attack, insurgents killed three civilians and wounded 20 more in a roadside bombing near a Sunni mosque in northeast Baghdad, the security official said.
The attack was against a police patrol near Al-Nida mosque in Baghdad's Al-Qahira neighbourhood.
Another three civilians were wounded in a another roadside bombing next to the Al-Mawal restaurant near central Baghdad's Al-Mustansiriyah university.
Earlier, six Iraqi border policemen were killed and another six wounded in a suicide car bomb attack in the town of Sinjar near the Syrian border.
Elsewhere six Iraqis were killed, including a representative of Shiite cleric Grand Ayatollah Ali al-Sistani and an officer in the oil protection force and his two bodyguards were kidnapped between Tikrit and Kirkuk.
One police officer was killed and four wounded by a roadside bomb attack east of Kirkuk. Police also found six corpses in Kirkuk overnight.
The latest string of bombings came ahead of Thursday's ceremonial start of a handover of Iraq's military command from the US-led coalition forces to Iraqi
authorities.
Regional dispute
Meanwhile the United Iraqi Alliance, the dominant Shiite parliamentary bloc, is promoting a "law of regional formation".
The legislation, if ratified, would mean that oil-rich Shiite southern Iraq can win self-rule on the model of the autonomous Kurdish north.
"The law will define how the regions are formed and whether it will be done by the governing council or through popular referendum," said party member Hamid Mualla al-Saadi.
Sunni lawmakers have vociferously opposed the draft law on autonomous regions, saying it is a prelude to a carve-up of the country.
The Sunnis say this would leave them with just the center and west of Iraq which has little oil of other resources.
But in recent days they appear to have softened their opposition, saying they would support the "administrative application of federalism" as long as a strong central government remains.
Military handover
Iraq also announced that it and the US military would sign a delayed accord today under which coalition forces will hand command of Iraqi armed forces to the government.
The agreement was initially due to be signed on September 2, but the handover ceremony was abruptly cancelled after disagreements on the Iraqi side over who should sign on the government's behalf.
Prime Minister Nuri al-Maliki is now expected to name a senior official to sign the agreement.
The accord means setting up a joint military command for the Iraqi army, navy and air force that will gradually take full operational control of the forces, including 115,000 US-trained ground troops.
Mr Maliki will also gain command of the 8th Iraqi Army Division, stationed in Najaf, with two new divisions every month afterwards. The Iraqi army has 10 divisions.
More British troops
In Basra, British forces confirmed they were reinforcing their 7,200-strong force with 360 additional troops, primarily to beef up their presence during an upcoming troop rotation.
The additional troops, which include engineers and Royal Marine commandos, will then be held over for several more weeks to assist in reconstruction work.
British Foreign Minister Margaret Beckett visited Basra on her second day in Iraq and stressed that peace in the south depended a lot on Iraqi security forces and not just "the British and coalition troops".