Obama 'preparing' anti-IS plan, expands Iraq strikes

US President Barack Obama has announced he will unveil a strategy to defeat Islamic State (IS) as the US expanded its air campaign against the militants, and Arab states vowed to take all "necessary measures" to confront the threat.

In another critical step in the battle against IS, the sharply divided Iraqi parliament will vote on a new government on Monday.

Premier-designate Haidar al-Abadi is hoping to bring some stability to Iraq's fractious politics at a time when it is struggling to combat the threat from IS militants who have seized control of swathes of the country.

The United States stepped up its month-long air campaign against IS on Sunday, striking targets around the strategic Haditha dam on the Euphrates River.

Iraqi forces sought to capitalise on the air strikes, which have largely been limited to the north since they began on August 8, attacking militants in the area and retaking the town of Barwana.

Obama made his political career opposing the war in Iraq and pulled out US troops in 2011, but has recently drawn flak for failing to outline a strategy to combat IS.

He announced he will make a speech on Wednesday to lay out his "game plan" to deal with the militants.

"I'm preparing the country to make sure that we deal with a threat from" IS, Obama said in an interview aired Sunday on NBC's "Meet the Press".

He said he would not announce the return of American ground troops to Iraq, and would focus instead on a "counter-terrorism campaign".

"We are going to systematically degrade their capabilities. We're going to shrink the territory that they control. And ultimately we're going to defeat them," Obama said.

Arab League chief Nabil al-Arabi, meanwhile, said the bloc's 22 members had agreed to confront IS.

"The Arab foreign ministers have agreed to take the necessary measures to confront terrorist groups including" IS, he told reporters in Cairo, without explicitly supporting US calls for a coalition to back its air campaign.

Iraqi flag raised

Sunday's US air strikes targeted an area that the militants have repeatedly tried to capture from government troops and their Sunni militia allies.

The strikes destroyed four Humvees, four armed vehicles, two fighting positions and a command post, the US Central Command said in a statement.

Pentagon spokesman Rear Admiral John Kirby said in an earlier statement that "the potential loss of control of the dam or a catastrophic failure of the dam -- and the flooding that might result -- would have threatened US personnel and facilities in and around Baghdad, as well as thousands of Iraqi citizens".

Iraqi troops and militia retook Barwana, east of Haditha, from the jihadists, who abandoned their weapons and vehicles in their retreat, an AFP correspondent reported.

"Joint forces backed by air support and tribesmen launched a wide attack to clear the areas surrounding the Haditha district," security spokesman Lieutenant General Qassem Atta told AFP.

The black IS banner was lowered from the town's main checkpoint and the Iraqi flag raised.

However, the victory was marred when a mortar round slammed into the town, wounding Anbar Governor Ahmed al-Dulaimi as well as Abdulhakim al-Jughaifi, the administrative official responsible for Haditha, and seven soldiers.

A suicide bomber then struck the convoy carrying Dulaimi to a nearby hospital, killing a soldier and wounding six.

The only previous US strikes against IS outside of northern Iraq were carried out in support of an operation by the army, Shiite militia and Kurdish fighters to break a months-long siege of the Shiite Turkmen town of Amerli, north of Baghdad.

Sustained US strikes could provide a major boost to pro-government forces in Anbar, where all of one city and chunks of another have been out of state control for more than nine months, along with other areas seized by militants since June.

If a new Iraqi government is not agreed on Monday, this will mean a return to the start of the contentious process, leaving the country rudderless at a critical time.

There have been repeated calls from the international community, including the United States, for a broad-based government to help confront the militants.

While this would ensure that all sides are represented, similar arrangements in the past have led to deadlock that has helped undermine government effectiveness.