(Recasts on Maliki comments) By Claudia Parsons and Dean Yates BAGHDAD, Feb 20 (Reuters) - Iraqi Prime Minister Nuri al- Maliki told his security forces on Tuesday to show no mercy towards insurgents in a security crackdown in Baghdad. Making a rare foray into Baghdad's violent streets, Maliki called for an end to sectarian divisions that threaten to tip the country into full-scale civil war. A suicide bomber and two car bombs killed at least 17 people in the capital on Tuesday. Iraqiya state television showed Maliki, a Shi'ite Islamist leader, talking to an Iraqi soldier near an armoured vehicle in central Baghdad. The soldier pointed to an area from where he said insurgents had been firing at security forces. "Don't just fire back, crush the place where the fire came from," Maliki replied. "Don't treat them with leniency. This is an armoured vehicle here, use it." The prime minister met Iraqis who had been forced out of their homes by sectarian fighting that has increasingly split Baghdad along Shi'ite and Sunni fault lines. He told them they would return to their neighbourhoods as "heroes". Maliki said on Friday the initial days of the U.S.-backed crackdown had been a "brilliant success" but a series of car bomb attacks that have killed scores of people has tempered any early optimism. U.S. generals, mindful of the failure of similar crackdowns last year, had warned militants could lie low initially but were likely to adapt their tactics. Shi'ite officials have said the failure of Operation Imposing Law could result in the collapse of the government and trigger even more bloodletting between majority Shi'ites and minority Sunni Arabs. MOURNERS TARGETED Among the attacks in Baghdad on Tuesday, a suicide bomber killed at least seven people and wounded 20 when he blew himself up at a mourning tent in the mainly Shi'ite area of Palestine Street in the northeast of the city, police said. A bomb also destroyed a truck carrying chlorine north of Baghdad, killing five people and spewing toxic fumes that affected nearly 140 others including many women and children, Iraqi police said. A source at police headquarters said the chlorine truck was rigged with explosives. It exploded near a restaurant at a rest stop on the main highway in Taji, 20 km (12 miles) north of Baghdad. The U.S.-led offensive against Shi'ite militias and Sunni insurgents had sharply reduced the number of death squad killings in Baghdad when it began a week ago. But the numbers have begun rising, to 20 on Monday and 25 on Tuesday, a police source said. It had dropped to just three on Sunday and in previous days to around five each day. Before the crackdown, police had been finding 40 to 50 bodies a day. (Additional reporting by Aseel Kami and Mussab al-Khairalla)
