With Sunni gunmen beginning to confront the Shiite-led government's security forces head-on in northern and western Iraq, fears are growing fast of a return to full-scale sectarian fighting that could plunge the country into a broader battle merged with the Syrian civil war across the border.

With more than 100 people killed over the past two days, it's shaping up to be the most pivotal moment for Iraq since U.S. combat troops withdrew in December 2011.

“Everybody has the feeling that Iraq is becoming a new Syria,” Talal Younis, the 55-year-old owner of a currency exchange in the northern city of Mosul, said Wednesday. “We are heading into the unknown. ...  I think that civil war is making a comeback.”

A crackdown by government forces at a protest site in the northern town of Hawija on Tuesday triggered the latest unrest. It has enraged much of the country's restive Sunni Arab minority, adding fuel to an already smoldering opposition movement and spawning a wave of bold follow-up clashes.

It is too soon to say whether the rage will lead to widespread insurrection in the largely Sunni cities of Mosul and Ramadi or, more significantly, spiral into open sectarian warfare in the streets of Baghdad.

The Iraqi capital is far more tightly controlled by security forces than the remote towns hit by the latest unrest, but insurgents continue to launch regular, well-coordinated waves of attacks inside Baghdad. Outright threats that all but disappeared as the last bout of sectarian fighting waned in 2008 are making a comeback too, like the leaflets signed by a Shiite militant group that began turning up on the doorsteps of Sunni households in Baghdad earlier this year.

The exact circumstances of the Hawija bloodshed remain murky, but there is outrage over the government's handling of the unrest and the fact that most of the 23 killed at the site were among the Sunni demonstrators.

Talal al-Zobaie, a Sunni lawmaker from the opposition Iraqiya bloc, described this week's events as a pivotal moment for the country.

“The crime in Hawija clearly shows that people have lost faith in their armed forces, which have been turned into a tool in the hands of the prime minister,” he said. “Some people now think that the only way to protect themselves is to take up arms.”

The raid in Hawija sparked clashes and a spate of other attacks, mostly targeting Sunni mosques, that killed at least 56 people on Tuesday. Raids by Sunni gunmen on army checkpoints broke out in the hours following the protest camp raid and continued into Wednesday.

In the most dramatic incident, armed tribesmen sealed off approaches to the Sunni town of Qara Tappah, about 120 kilometers (75 miles) northeast of Baghdad. When Iraqi troops backed by helicopters arrived to try to clear the makeshift roadblocks, fierce clashes erupted. Police say 15 gunmen and seven soldiers were killed.

Sunni tribesmen also battled soldiers throughout Wednesday in the town of Suleiman Beg, about 150 kilometers north of Baghdad. Four soldiers and 12 others, including gunmen, were killed.

The sense that violence could be spreading from a local dispute to other parts of the country is particularly worrying to many Iraqis.

“This could open the door for broader clashes if things are not contained soon,” said Mahmoud Othman, a Kurdish lawmaker. “Hawija is a small town and it can be controlled, but the real problem will arise if Mosul or Ramadi decide to enter the armed struggle,” he said.

Three gunmen were killed Wednesday when they attacked a security checkpoint near the former al-Qaida stronghold of Mosul, about 360 kilometers northwest of Baghdad.

Later, a car bomb struck a police patrol north of Baghdad, killing a policeman and two civilians. Another car bomb exploded after sunset near a bus stop in Baghdad's mostly Shiite neighborhood of Husseiniyah, killing seven people and wounding 23.

Hospital officials confirmed the casualty figures. All officials spoke on condition of anonymity because they were not authorized to release the information to reporters.

Human Rights Watch urged Iraqi authorities to ensure that any investigation into the Hawija killings Tuesday take into account allegations that security forces used excessive force. The rights group noted that there have been reports that security forces attacked demonstrators without provocation.

Iraq's Defense Ministry said it entered the protest area to try to make arrests over an attack on a nearby checkpoint several days earlier, and its forces came under heavy fire from several types of weapons, as well as from snipers.

“This is one of those cases where ... a singular spark escalates tensions and mobilizes the population for renewed conflict,” said Ramzy Mardini, an analyst at the Beirut-based Iraq Institute for Strategic Studies.

“War fatigue in Iraq is losing its pacifying effects and the rationale to pick up arms and fight again is finding fertile ground in Sunni land(s).”

The increasingly sectarian lines drawn in the Syrian civil war and the rise of Sunni Islamists in the region in the wake of the Arab Spring is also having an effect on the Sunni protest movement playing out in Iraq, he noted.

Syrian President Bashar Assad's regime is fighting against largely Sunni rebels who draw support from Turkey and Sunni Gulf states. Assad's Alawite sect is a branch of Shiite Islam, and his regime is backed by Shiite powerhouse Iran.

“Given what's happening at the regional level, there's a dangerous mixture of Sunni hubris and Shiite fear. These emotions coupled with political volatility and uncertainty renders an environment where miscalculations are most likely to occur,” Mardini said.

At the same time, recent local elections _ which have not yet been held in two largely Sunni provinces _ have put Iraqi politicians of all stripes in campaign mode, and playing up their sectarian credentials is a way to rouse voters.

“You're not going to find Sunnis urging for calm,” Mardini said. “Most ... are still in the mode of rabble-rousing and throwing the reddest of meats to a discontent and frustrated electorate.”

Tuesday's bloodshed followed four months of largely peaceful protests staged by Iraq's Sunni minority against the government. 

Many Sunnis are angered over what they see as an effort by Prime Minister Nouri al-Maliki to sideline members of their sect within the power-sharing government. They say they face discrimination, particularly in the application of a tough anti-terrorism law that they believe unfairly targets them. The government frequently carries out arrests in Sunni areas on charges of ties to al-Qaida or the deposed Baathist regime of Saddam Hussein, a Sunni.

Emma Sky, a key civilian policy advisor for U.S. Army Gen. Ray Odierno when he was the top U.S. military commander in Iraq, said the events in Hawija exacerbate concerns that the conflicts in Syria and Iraq are merging.

“The fear is that the post-World War I settlement is unraveling,” she said, referring to the agreement between Britain and France that divided up the heart of the Middle East and drew the modern borders of Syria and Iraq.

“The way to inoculate Iraq against all of this is national unity,” she said. “If Iraq had wise politicians who actually came together for the good of the country, it could go in a different direction.” (AP)