Twelve Iraqi policemen were killed and 10 others wounded on Friday in an attack launched by an unknown group of fighters on al-Amil police station, near the airport road in western Baghdad.
According to Iraqi police sources, the attackers freed all prisoners detained at the police station and set ablaze three police vehicles.
"The attackers freed more than 50 prisoners," Iraqi journalist Ziad al-Samarrai told Aljazeera.
"The 30 attackers or so seemed to be well armed and had prior information about their target."
Al-Samarrai said it was not yet known whether the purpose of the attack was political or to release prisoners.
Fighters accuse the country's fledgling police force of complicity with the US.
The highway leading to Baghdad International Airport is considered one of the most dangerous stretches in the country.
Friday's attacks broke a brief lull
in the violence convulsing Iraq
Later on Friday morning, 14 Iraqis were killed and 19 more wounded in a car bombing in Baghdad's northern al-Adhamiya district.
"The explosion happened at around 7.00am (0400 GMT) near Hamid al-Alwan mosque, killing 14 and wounding 19," an interior ministry spokesman said, adding that it was not immediately clear if the casualties were police or civilians.
"There was a suicide bomber in the car," and the blast had caused extensive material damage, he said.
Warplanes in action
Al-Adhamiya suburb came under heavy mortar attack on Friday morning and thick smoke was seen rising over the former presidential compound, Aljazeera has learned.
"Intermittent clashes have been under way between resistance fighters on one side and US and Iraqi National Guard forces on the other," Al-Samarrai told Aljazeera.
"US warplanes were seen flying over the area and a large number of US troops were being deployed."
Reinforcements arrive at al-Amil
police station after the attack
Both attacks in the capital have been claimed by Jordanian-born Abu Musab al-Zarqawi's organisation, al-Qaida Group of Jihad in the Country of Two Rivers, according to a statement on a website.
Separately, in northern Iraq, five people were killed and another 17 wounded in a clash between US troops and armed fighters after Friday prayers in the Yarmook suburb of Mosul, about 350km from Baghdad.
The headquarters of the provincial governorate and the National Union Party in the city came under mortar attack.
And near the oil-rich town of Kirkuk, a US soldier was killed and two others were wounded when their convoy was attacked, the US military said.
With violence suddenly surging on Friday, Dr Rafi al-Isawi, director of Falluja Hospital, was wounded along with two of his colleagues when US troops opened fire on the ambulance they were travelling in.
Al-Isawi and his colleagues were in Falluja after they were given the green light from the interim Iraqi health ministry and US troops to rehabilitate health centres in the city, sources said.
The Falluja offensive left homes
and health centres devastated
Aljazeera has learned that more than 4000 people who fled Falluja and have been staying in tents and abandoned government buildings in the Saklawiya area, north of the town, are facing harsh living conditions as a result of shortages of basic necessities including food, drinking water, and medicine.
Also on Friday, Lieutenant-Colonel Ali Husain al-Dayini, officer in charge of the police central investigation department in Diyalli governorate, and a member of his entourage were killed in Baldaroz town, southeast of the governorate.
An unknown armed group opened fire on al-Dayini's car while he was on his way to work.