BAGHDAD (AFP) - Iraqi Prime Minister Nuri al-Maliki is facing one of the biggest challenges of his eight-year rule, with key areas on Baghdad's doorstep outside government control just months before general elections.

He is also often accused of marginalising and targeting Iraq's Sunni Arab minority, many members of which oppose his government, and has presided over a sharp increase in violence in the country to levels not seen in five years.

The city of Fallujah, just 60 kilometres west of Baghdad, has been out of government hands for days, while parts of Anbar provincial capital Ramadi, farther west, are also under the control of militants.

But analysts believe that if the 64-year-old Mr Maliki is able to obtain some type of security victory, he may yet be able to emerge relatively unscathed and focus attention away from other failings, as he has done in the past.

"Maliki faces the biggest challenge since 2006," said Ihsan al-Shammari, a political science professor at Baghdad University. "The issue of Fallujah is related to the issue of terrorism, and its importance exceeds other files such as services," which Mr Maliki's government has also failed to improve, Mr Shammari said.

"The biggest challenge is ISIL," he said, referring to Al-Qaeda-linked group the Islamic State of Iraq and the Levant, which has been active in the fighting in both Fallujah and Ramadi. But "if Mr Maliki succeeds in containing the situation" in Anbar, it will be a major boost for the premier ahead of parliamentary polls scheduled for April 30.

Fighting erupted near Ramadi on December 30, when security forces cleared a year-old Sunni Arab anti-government protest camp.

The violence spread to Fallujah, and militants moved in and seized the city and parts of Ramadi after security forces withdrew.

The loss of Fallujah is strategically important due to its proximity to the capital, and symbolically signficant because it was the target of two major assaults by American forces in which they saw some of the heaviest fighting since the Vietnam War.

More generally, Iraq has suffered a surge in violence to levels not seen since 2008, when the country was just emerging from a brutal period of sectarian killings that left tens of thousands dead.

"Entering into military operations without clear coordination with the residents of the area will lead to a major disaster," Issam al-Faili, a political science professor at Mustansiriyah University in Baghdad, said of Fallujah.

"There are fighters experienced in urban warfare in the city," who know Fallujah well, Faili said.

If he succeeds in Fallujah, Mr Maliki will likely use it for political gain in the runup to the polls, as he did with the "Charge of the Knights" operation in Basra in 2008, Mr Faili said.

Maliki, who was born near the city of Karbala, south of Baghdad, has faced repeated accusations of sectarianism from Sunni Arabs who ruled the country for decades before the 2003 US-led invasion. Widespread anger among Iraqi Sunnis has fuelled the rise in violence in the country that began last year, experts say.

But Mr Maliki, who fled Iraq in 1980 to escape execution by Saddam Hussein's regime, still enjoys the backing of the United States, though some US lawmakers have expressed concerns over how he would employ advanced American weaponry.

"Maliki relies on Western, and especially American, support," said Hamid Fadhel, a Baghdad University political science professor. "It is clear that the American position is a strong message to Mr Maliki's opponents, especially the Sunni Arabs who tried to convey a message that Mr Maliki is targeting them," Mr Fadhel said.

He added that "this international support, at least permitting Iraq to be equipped with drones and missiles, is evidence that the United States backs Mr Maliki," and may not object to him seeking a third term as premier.

Mr Maliki, who has a perpetually-light beard and dresses in sharp suits and ties, has repeatedly clashed with some of those who first brought him to power in 2006, especially powerful Shiite cleric Moqtada al-Sadr.

Aside from security concerns and accusations of sectarianism, Mr Maliki's main challenges are ultimately from "his Shiite opponents, and not from the Sunnis," Mr Fadhel said.