Gunmen seized Adel Qazaz from his car in northern Baghdad on Sunday even as Iraqi police continued to search for the chief of the national Olympic Committee, Ahmed al-Hadjiya, who was abducted from a meeting along with 30 others a day earlier.
Al-Hadiya's colleagues said on Sunday that six of those captured on Saturday had since been released. Two bodyguards, however, are known to have been killed during and immediately after the mass abduction.
In further violence highlighting the security challenges facing the national government of Nuri al-Maliki, a suicide bomber blew himself up in a popular cafe north of Baghdad.
At least 20 people were killed and 25 wounded, police and hospital sources said. Most of the victims were older men.
Aljazeera channel reported that t
he cafe was close to a Shia mosque in an area populated by Turkmen Shia, and that rescuers were searching through the rubble for survivors.
The blast took place in the town of Tuz Khurmatu, 170kms north of Baghdad, Colonel Abbas Mohammed told Reuters.
Blow to oil sector
The kidnapping of Qazaz is a blow to the country's vital oil sector, which has been trying to attract foreign investment to rebuild its dilapidated infrastructure.
Iraq's oil sector has been hit by
violence, smuggling and corruption
He was the second top oil official to have been kidnapped in little over a month.
Muthana al-Badri, director general of Iraqi's State Company for Oil Projects, has not been seen since gunmen abducted him from his car on June 8.
The oil sector, seeking to recover from decades of war and sanctions, has been hit by rebel attacks as well as smuggling and corruption.
Oil provides almost all of Iraq's state revenues and is seen as crucial to its economic recovery.
Qazaz's North Oil Company is in charge of Iraq's northern oil fields. Exports from the fields, briefly restored last month after a lengthy suspension, have been at a standstill again since last week.
An oil ministry official stressed that work at the company would continue as normal on Monday, despite Qazaz's kidnapping.
Other unrest kills 19
In addition to the cafe blast, at least 19 people were killed in shootings and bombings in Iraq on Sunday.
In one audacious attack, gunmen raided the main hospital in the city of Baquba north of Baghdad, killing four policemen and freeing 13 wounded prisoners.
A British soldier was also killed and another wounded during an early morning raid to capture a suspected "terrorist" in the southern Shia city of Basra.
Meanwhile, Saddam Hussein and three co-accused in his trial on crimes against humanity spent a ninth day without food, the US military said, adding the four were in good health.
They are staging a hunger strike to demand better protection for defence lawyers after a third was killed last month.