The United Nations has tripled its appeal for humanitarian funding for Iraq in 2014 to more than $312 million, with the country battling a fierce militant onslaught.

A lightning offensive by Sunni militants in recent weeks has overrun swaths of five Iraqi provinces, killed nearly 1,100 people and displaced hundreds of thousands.

A suicide bombing and shelling killed 12 people and wounded at least 23 south of Baghdad Wednesday, officials said, as Iraq struggles to stem a major militant offensive.

The bomber detonated explosives in a market in Mahmudiyah, while shellfire struck various areas of the town.

U.S. Secretary of State John Kerry will travel to Saudi Arabia on Friday for talks with King Abdullah about the crisis in Iraq.

Speaking on the sidelines of talks at NATO, Kerry announced the extra stop on his current whirlwind tour saying he would stress "the great urgency" of the conflict in Iraq and brief Saudi leaders on his visits to Baghdad and Arbil this week.

Turkey raised fears on Wednesday over potential spillover from turmoil in neighboring Iraq, as NATO promised not to hesitate to defend its ally from the widening conflict.

Speaking on the sidelines of a NATO gathering in Brussels, Turkish Foreign Minister Ahmet Davutoglu called for greater cooperation with its allies to meet the threat posed by the rise of extremist militants in Iraq and the continuing civil war in Syria.

Jordanian police fired tear gas to disperse angry protesters in the Islamist stronghold of Maan on Wednesday after police killed a suspect in a shootout in the southern city.

"More than 100 people demonstrated to protest the killing of a man wanted by police," a witness told AFP on condition of anonymity.

A deadly attack on troops and low turnout Wednesday marred Libya's general election on which hopes were pinned of ending three years of turmoil since dictator Moammar Gadhafi's ouster.

At least three soldiers deployed to provide polling day security in second city Benghazi were killed in what security officials said was an attack on their convoy by Islamist militia.

In the Iraqi town of Taza Khurmatu, a motley brigade of Shiite Turkmen locals adjust their weapons and headscarves before heading out to defend their homes from encroaching Sunni militants.

The men range from those in their teens, yet to grow a mustache or see combat, to elders approaching retirement and weary of war.

Dubai's Emirates Airlines said Wednesday it has suspended flights to Peshawar, in northwest Pakistan, after gunmen opened fire at a landing plane killing a passenger and wounding two crew members.

"Emirates has suspended flights to and from Peshawar effective 25 June 2014 until further notice, due to the security situation at the destination," an Emirates statement said.

Palestinian President Mahmud Abbas said in a letter to Bashar Assad that his election as Syrian president will help to end the country's three-year war, Damascus said on Wednesday.

"Your election to the presidency of the Syrian Arab Republic guarantees Syria's unity and sovereignty, and starts of a countdown to the end of Syria's crisis and its war against terrorism," Abbas wrote, according to the Syrian presidency's Facebook page.

A senior army officer said on Wednesday that Jordan can defend itself against "any aggression" after Sunni Arab militants seized large swathes of neighboring Iraq.

"The Jordanian-Iraqi borders are safe. The Jordanian armed forces are capable of defending the kingdom from any aggression," border guard commander Brigadier Saber Mahayrah told reporters as they toured the border area.