(Repeats story from Dec. 4 without changes)
* More than 40 found dead within three days
* Some bodies blindfolded, bound arms
* Al Qaeda suspected behind most attacks
By Suadad al-Salhy
BAGHDAD, Dec 4 (Reuters) - A spate of execution-style killings in Iraq has rekindled memories of attacks carried out at the height of the country's sectarian bloodshed and raised fears of a widespread return to such violence.
In the past week Iraqi police have found the bodies of at least 41 men who were either shot in the head or decapitated in a wave of killings in Baghdad and northern Iraq.
Iraqi security officials say these targeted killings have more to do with attempts to fuel instability, and with infighting within the two Muslim sects, than with direct hostility between Shi'ite and Sunni communities.
They believe the killings are not directly related. But they warn that such chaos could set off wider sectarian violence, especially when combined with an insurgent bombing campaign led by al Qaeda, which is expected to get worse ahead of parliamentary elections in April next year.
"The phenomenon of unknown bodies of young men who have been beheaded or executed has significantly increased," said Hakim al-Zamili, a senior Shi'ite lawmaker and member of parliament's Security and Defence Committee.
Iraqis use the term "unknown bodies" because attackers have removed traces of identity from the corpses such as personal papers or, in some cases, their heads.
Such attacks have been happening on a smaller scale for the past two months, Zamili said.
"We have information that there are many executed people in the morgues of the hospitals in Salahudin, Mosul and Anbar," he said, naming areas in northern and western Iraq.
Security officials say al Qaeda-linked Sunni insurgents may be behind most of the recent killings, but they also suspect Shi'ite militia could have been involved in some of them.
The wave of killings is designed to drag the country into civil war, Zamili said, predicting that murders, abductions and security breaches will only get worse as campaigning politicians increase their divisive rhetoric.
"We are very worried because of this, we are afraid of reactions that could spin out of control."
Execution-style killings were one of the hallmarks of sectarian violence that peaked in 2006 and 2007. Iraqis used to find dozens of bodies each morning, discarded in public squares and garbage dumps, particularly in the capital.
This year has been one of the most violent in Iraq since that wave of violence which killed tens of thousands. More than 8,000 Iraqis have been killed since the start of 2013, the United Nations said on Sunday.
The instability is partly fuelled by the Syrian conflict next door, which has a strong sectarian element. Al Qaeda-linked militants are operating on both sides of the border and have been able to take advantage of an increasingly polarised Iraq.
Most people are killed in bomb attacks, but the targeted murders have added a frightening new dimension to the violence.
"I am profoundly disturbed by the recent surge in execution-style killings that have been carried out in a particularly horrendous and unspeakable manner," U.N. envoy Nickolay Mladenov said on Sunday.
The deadliest attack was uncovered on Nov. 29 when police retrieved the bodies of 18 men, including a Sunni tribal sheikh and his son, who had been abducted and shot in the head near Baghdad. A security official said the attack appeared to have been carried out by the Iraqi wing of al Qaeda.
The bodies were found in an orchard in Meshahda, a mainly Sunni area around 30 km (20 miles) north of Baghdad.
Their abductors were disguised in army uniform, police said, and the victims may have been chosen because they were seen as supporters of Prime Minister Nuri al-Maliki's government.
On the same day, in a second attack further north, police found the beheaded corpses of seven male labourers. They had been dumped in a yard in a northern neighbourhood of Tikrit, a city 150 km (90 miles) north of Baghdad.
On Nov. 27 police retrieved the corpses of eight men, blindfolded and handcuffed, in the mainly Sunni Muslim area of Arab Jubbor, south of Baghdad, where al Qaeda has been active.
One the same day in the northwest of the capital, five bodies were found in the Shi'ite Shu'ala district, also handcuffed, blindfolded and executed, police said. A further three were found in Baghdad's Shi'ite's district of Sadr City.
A senior federal police official, speaking on condition of anonymity, said that a Shi'ite militia was likely behind the two later attacks, although it was not clear exactly which one.
Officials say such killings will increase ahead of the elections as groups seek to undermine Maliki, seen by his Shi'ite rivals as the strongest contender.
"He is the commander of the armed forces and (the attacks) increase his inability to maintain security," the police official said.
Shi'ite militias ceased fighting in Iraq after 2011, but some groups are thought to have continued carrying out assassinations. Many members entered the regular security forces but kept ties to their old groups.
"The situation is very dangerous," a Shi'ite politician close to Maliki said.
Maliki's main rivals have publicly accused Asaib al-Haq, the well-trained and well-equipped Shi'ite militia supportive of Maliki, of being involved in some of the attacks.
Asaib al-Haq, which carried out some of the most prominent attacks on foreigners during the Iraq war, denied involvement.
"Anyone who belongs to Asaib al-Haq is strictly prohibited from engaging in such actions," spokesman Ahmed al-Kinani said.
Officially all Shi'ite factions are against the killings, he said, but some extremists who believe that they are supporting the sect probably carried out some of the assassinations in reaction to other attacks.
Iraqi authorities have reinforced security in the targeted areas, said Ali al-Moussawi, a media adviser to Maliki. He said there was no connection between Maliki and any armed militia.
Jaber al-Jabiri, a Sunni lawmaker in the opposition Iraqiya political bloc, said the killings are happening because there are armed groups on both sides - Sunnis and Shi'ites - who do not want the political process to proceed.
"They aim to live in the chaos because they cannot survive without it," he said. (Additional reporting and writing by Sylvia Westall; Editing by Giles Elgood)