It was day of violence as well as political unrest in Iraq: Police in Diyala province northeast of Baghdad reported two separate bombings in which six people were killed, and officers also found 13 bullet-ridden bodies.
In Basra, Iraq's second-largest city and the urban center of an oil-rich region, Shiite groups have been wrestling for control of the area.
Residents are becoming increasingly alarmed about security, saying that killings, kidnappings and other crimes have increased significantly since British forces turned over responsibility for the city at the end of last year.
In February, two journalists working for CBS were kidnapped in Basra. One was released but the other, a Briton, is still being held.
A long line of marchers, estimated to be as many as 5,000 people, demonstrated near the Basra police command headquarters Saturday, demanding that the police chief, Maj. Gen. Abdul-Jalil Khalaf, and the commander of joint military-police operation, Lt. Gen. Mohan al-Fireji, resign.
Many carried banners, decrying the killing of women, workers, academics and scientists. Dozens of women were slain in Basra by religious extremists last year because of how they dressed, their mutilated bodies found with notes warning against "violating Islamic teachings."
Saturday's protesters, overwhelmingly men, came from several Shiite political movements, including the biggest Shiite party, the Supreme Islamic Iraqi Council and its militia wing, known as the Badr Brigade.
Khalaf said at a news conference later that "today's demonstration was a natural right of the citizens and the political parties to express their opinions."
He defended the performance of the police, saying they had freed 10 people who were kidnapped in the past 10 days and "detained 64 people accused of carrying out sabotage and terrorist operations all over Basra."
There was violence, meanwhile, in Diyala province northeast of Baghdad where an official in the joint police-army operations center said that separate roadside bombings killed six people in Wajihiyah, about 25 kilometers east of the provincial capital of Baqouba.
In the first attack, a bomb destroyed a car - killing a mother and her two children and wounding two others, including the woman's husband. The second attack hit a bus, killing three men and wounding two others, said the official, who spoke on condition of anonymity.
Police also found the bullet-riddled bodies of 13 men in Khalis, 50 miles north of Baghdad, the official said.
Meanwhile, the U.S. military confirmed that it had released the news editor of a prominent Shiite-run television station on Friday afternoon, after he was cleared on having connections to so-called "special groups" militias - a term often used by the military to describe Shiite extremists who have broken with anti-U.S. cleric Muqtada al-Sadr.
Hafidh al-Beshara, the news editor and manager of political programming for Al-Forat TV, was detained two weeks ago along with his son, who is still being held.
Mass Grave Found By Iraqi Forces, May Contain 100 Bodies
Iraqi security forces have discovered a mass grave in Diyala province containing perhaps 100 bodies, the U.S. military said Saturday.
The grave, near Khalis about 50 miles north of Baghdad is still being investigated but the military said the skeletal remains appear to have been buried a long time ago.
Police Col. Sabah al-Ambaqi said the grave was discovered in an orchard near al-Bu Tumaa, a Sunni village outside Khalis. He said authorities including both Iraqi and U.S. forces were conducting a search when a foul smell led them to the grave site.
Early reports were that 13 bullet-ridden bodies had been found in the area, but al-Ambaqi said they turned out to be part of the larger grave site.
Khalis is a Shiite town but it is surrounded by Sunni communities and has been the scene of repeated sectarian attacks.
Separately, an official from police in the Dora neighborhood of Baghdad, who spoke on condition of anonymity because he was not authorized to release the information, said Iraqi police and local awakening council members found 11 decomposed bodies with bullet wounds on Saturday. Awakening councils are made up of Sunni fighters who have accepted U.S. backing to switch allegiances and fight al Qaeda in Iraq.