Thousands of people took to the streets Saturday in southern Basra, protesting deteriorating security in a city where Iraqi forces assumed responsibility for safety last December. 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. 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. 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 km east of the provincial capital of Baquba. 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. Meanwhile, security forces found about 100 badly decomposed bodies in a mass grave north of Baghdad, the US military said on Saturday, one of the largest such finds in the country for months. US and Iraqi security forces said it was not clear who was responsible for the grave near Khalis, 80 km (50 miles) north of Baghdad, or when the victims had been killed. “Initial reports indicate it may contain the remains of approximately 100 people,” said US military spokesman Major Winfield Danielson. Iraqi police said they suspected those in the grave were likely to have been killed some time after the 2003 US-led invasion to topple Saddam Hussein. Separately, the US 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-US cleric Moqtada 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. __