* Sunni protests, violence increasing tensions
* Islamist insurgents seeking to stir sectarian strife
* War in neighbouring Syria worsening Iraq's crisis (Adds details on demands)
By Kareem Raheem
BAGHDAD, Jan 22 (Reuters) - Three blasts, including a suicide attack near an army base, killed least 17 people across Baghdad on Tuesday, the latest violence to feed worries that Iraq's unrest may slide into widespread sectarian confrontation.
Insurgent bombers are seeking to enflame tensions as Shi'ite Prime Minister Nuri al-Maliki faces increasing pressure from mass Sunni Muslim protests and a separate dispute with the country's autonomous Kurdistan region over the control of oil.
The most deadly of Tuesday's explosions took place in Taji, 20 km (12 miles) north of Baghdad, where a suicide bomber driving a car packed with explosives detonated his bomb near an army base, killing at least seven people and wounding 24.
Another parked car bomb exploded in a crowded market in the Shi'ite neighbourhood of Shula, northwestern Baghdad, killing five people and wounded 13, police and hospital sources said.
"We received a call for us to head to the blast site, it was a car bomb. A woman was laying dead with a sack of groceries still beside her, and the wounded were screaming," said policeman Ghalib Ameer, whose patrol was called to Shula.
In Mahmudiya, a town 30 km (20 miles) south of Baghdad, a car bomb attack near an army checkpoint killed five people, including two soldiers and wounded 14 more.
Violence in Iraq has eased since the widespread sectarian carnage of 2006-7, but Sunni Islamist insurgents often tied to a local al Qaeda affiliate still launch frequent attacks to reignite confrontation among the Shi'ite majority, Sunni Muslims and ethnic Kurds.
Thousands of Sunni protesters are camped out in western Anbar province in what is developing into a major challenge to Maliki, whose power-sharing government, split among Shi'ites, Sunnis and Kurds, has been bogged down in infighting since the last U.S. troops left a year ago.
The Shi'ite premier is trying to ease Sunni protests that erupted a month ago after officials arrested members of a Sunni finance minister's security team on terrorism charges. Sunni leaders saw that move as a crackdown.
Since the fall of Saddam Hussein after the U.S.-led invasion a decade ago, many Iraq Sunnis feel they have been marginalised by the Shi'ite leadership and say Maliki is amassing power at their community's expense.
Maliki has appointed senior Shi'ite figure Deputy Prime Minister Hussein al-Shahristani to investigate the protesters' demands.
Authorities said on Tuesday they had so far released more than 800 detainees unjustly held or whose sentences had ended.
But thousands of protesters camped out on a highway in the Sunni heartland of Anbar, the vast desert province that was once the centre of al Qaeda's fight against American troops, say they are determined to stay out until their demands are met.
Sunni leaders want the modification of anti-terrorism laws and more control over a campaign against former members of Saddam's outlawed Baath party, both measures they believe unfairly target their minority community.
The unrest is fanning concerns the conflict in neighbouring Syria will upset Iraq's own delicate ethnic and sectarian balance. More hardline Sunni Islamists want Maliki to step down or even the establishment of an autonomous Iraqi Sunni region. (Reporting by Kareem Raheem and Ahmeed Rasheed; writing by Patrick Markey)