A suicide car bomber blew up his vehicle at the entrance to a US military base north of Baghdad, killing at least 11 Iraqis and wounding 20 others and two American soldiers, the US military said.
The attack occurred at a military base near Baiji, an oil-refining town 180km north of Baghdad.
Iraqi police Captain Sabah Mahmoud said the bomber drove a black BMW car toward the base and detonated it at the entrance.
"I saw five cars ablaze and people scattered everywhere," said Amir Ismael, a 38-year-old man wounded in the abdomen and thigh.
At least 25 people were killed and many wounded by an explosion, which tore through the headquarters of a Kurdish party in Baghdad, police at the scene said.
The blast was at the offices of the Patriotic Union of Kurdistan, close to Iraq's Foreign Ministry and an entrance to the "Green Zone" compound where the US-led administration in Iraq is based. Shooting rang out after the explosion.
Policeman Sattar Jabar said he had seen at least 25 bodies and that more than 20 people had been wounded.
A huge crater was blown into the ground at the entrance to the building.
The blast came as US and Iraqi officials announced the names of an Iraqi government due to formally take over sovereignty from the occupying powers on June 30.
Saad Adnan a driver at the transport ministry, said he was driving past the PUK headquarters when it was hit by the blast.
He said guards at the building opened fire after the blast, killing some bystanders.
Adnan said he saw several bodies. "One of the dead was a woman. Only her head was left," he said.
The blasts came on the day Iraq's new government was sworn in with Sunni tribal leader Ghazi al-Yawar as president, but there were no celebrations as a bloody wave of explosions killed at several people on Tuesday.
The US-installed Governing Council nominated Yawar. His appointment was confirmed by UN special envoy Lakhdar Brahimi, and fills a position vacant since dictator Saddam Hussein was toppled in April last year.
A senior official from the US-led coalition said the Governing Council, a body that has been heavily criticised by ordinary Iraqis as unrepresentative, was dissolved with the naming of the incoming government.
"The Governing Council was dissolved this morning. The interim government will take over responsibilities as of today, until sovereignty is fully transferred on June 30," the official said, requesting anonymity.
Yawar's appointment to the largely ceremonial position at the top of the government, which will formally take over after the June 30 transfer of power, followed days of tumultuous talks between the council and the coalition.
In his first press conference alongside Brahimi and prime minister Iyad Allawi, who was named last week and who unveiled his cabinet Tuesday, Yawar called for "full sovereignty" to be restored through a new UN resolution.
"We the Iraqis also look forward to being granted full sovereignty through a Security Council resolution to enable us to rebuild a free, independent, democratic and federal, unified homeland," he said.