BAGHDAD - A string of deadly blasts shattered an early round of voting in Iraq Thursday, killing 17 people and highlighting the fragile nature of the country's security gains ahead of crucial parliamentary elections on Sunday. Iraq security forces were out in full force, trying to protect early voters in an election that will determine who will lead the country through the crucial period of the U.S. troop drawdown and help decide whether the country can overcome its deep sectarian divisions. But three explosions …quot; a rocket attack and two suicide bombings …quot; showed the ability of insurgents to carry out bloody attacks. They have promised to disrupt the voting with violence. "Terrorists wanted to hamper the elections, thus they started to blow themselves up in the streets," said Deputy Interior Minister Ayden Khalid Qader, responsible for election-related security across the country. Thursday's voting was for those who might not be able to get to the polls Sunday. The vast majority of early voters were the Iraqi police and military who will be working election day …quot; when the rest of the country votes …quot; to enforce security. Others voting included detainees, hospital patients and medical workers. Many of the blast victims were believed to be security personnel, targeted by suicide bombers who hit police and soldiers lined up to vote. Convoys of army trucks and minibuses ferried soldiers and security personnel to and from polling stations. Many stores were shuttered, and normally crowded streets were nearly empty, as people stayed home on a holiday declared by the government. About 19 million of Iraq's estimated 28 million people are eligible to vote in the elections, and Iraqi expatriates can cast ballots in 16 countries around the world. In the first attack, a Katyusha rocket killed seven people in the Hurriyah neighborhood about 500 yards (meters) from a closed polling station, police said. The second attack hit the upscale Mansour neighborhood, where a suicide bomber detonated an explosive vest near a group of soldiers lining up at a polling station, killing six and wounding 18, police said. The blast left a small crater in the middle of the street, and debris from the explosion splattered around the crater. Pools of blood and burnt human flesh littered the ground along with broken glass, rubble from buildings and the remnants of shops signs.