* Blasts hit Shi'ite districts across Baghdad
* Sunni insurgents trying to spark widespread violence
* Violence accompanying growing political unrest (Adds details throughout)
By Kareem Raheem
BAGHDAD, Feb 17 (Reuters) - Several car bombs exploded in Shi'ite Muslim neighbourhoods across Iraq's capital Baghdad on Sunday morning, killing at least 26 people in blasts that tore into shops, restaurants and busy commercial streets.
No-one claimed responsibility for the attacks but Sunni Muslim insurgents have stepped up their operations since the beginning of the year in a bid to undermine the Shi'ite-led government and trigger deeper intercommunal fighting.
One blast tore off shop fronts in Qaiyara district while another left the remains of a car and its twisted engine littered across a high street in the busy, commercial Karrada district packed with restaurants and shops.
"I was buying an air conditioner and suddenly there was an explosion. I threw myself on the ground. Minutes later I saw many people around, some of them dead, others wounded," said Habibiya district salesman Jumaa Kareem, his jacket spattered with blood.
Sunday's blasts followed the assassination of a senior Iraqi army intelligence officer on Saturday, the latest in a wave of suicide bombings since January. No one claimed responsibility for that attack.
SUNNIS FEEL MARGINALISED
Many Iraq Sunnis feel they have been sidelined and unfairly targeted by security forces since the fall of Saddam Hussein and the rise of the country's Shi'ite majority through the ballot box.
Prime Minister Nuri al-Maliki's fragile power-sharing government, made up of Shi'ite, Sunni and ethnic Kurds, has been paralyzed by political infighting since American troops, who invaded the OPEC country to oust Saddam in 2003, withdrew more than a year ago.
Violence is still far from the mass sectarian bloodletting that killed tens of thousands in 2006-2007, though insurgents have carried out at least one big attack a month since the last U.S. troops left.
More than 10 suicide attackers have struck security forces, Shi'ite targets and a Sunni lawmaker since the start of January.
In the most recent attacks, a suicide bomber killed the head of the army's intelligence school on Saturday after storming his home in a northern town. Another suicide bomber killed 26 at a Shi'ite funeral at the start of the month.
There are fears the war in neighbouring Syria - where Sunni rebels are fighting to oust President Bashar al-Assad, an ally of Shi'ite Iran - could further destabilise Iraq's delicate sectarian and ethnic balance. (Additional reporting by Suadad al-Salhy; writing by Patrick Markey; Editing by Andrew Heavens)