Despite mounting pressure to step aside, Iraq's Nouri al-Maliki vowed Friday not to abandon his bid for another term as prime minister and pledged to stay on until the Sunni militants who have overrun much of the country are defeated.

The sharp words are certain to prolong the political impasse gripping Iraq, which is facing urgent demands for a new government that can hold the nation together in the face of an onslaught that threatens to cleave it in three along ethnic and sectarian lines.

The offensive by militants who have swept across much of northern and western Iraq since last month has been fueled in part by grievances among the country's Sunni Muslim minority with al-Maliki and his Shiite-led government.

Al-Maliki, a Shiite who has been prime minister since 2006, has been accused by former allies and others of monopolizing power and contributing to the crisis by failing to promote reconciliation with Sunnis.

The U.S. has urged the formation of a more inclusive government but has not explicitly called for al-Maliki to bow out.

In what has been seen as a rebuke of al-Maliki, Iraq's top Shiite cleric, Ayatollah Ali al-Sistani, has pressed lawmakers to quickly form a new government that can confront the militant threat and unite the country. Lawmakers failed in their first session of parliament on Tuesday to make any progress.

On Friday, al-Sistani lamented the inability of political leaders to agree on a new prime minister and urged them to redouble their efforts, a cleric who represents him told worshippers in a sermon in the holy city of Karbala.

Al-Maliki's State of law bloc won the most parliamentary seats in April elections, which would traditionally make him the leading candidate to head a new government. But al-Maliki failed to gain a majority in the legislature, meaning he needs allies to form a government.

That has set the stage for intense wrangling over the makeup of a coalition -- and, above all, who will be prime minister.

Al-Maliki made clear on Friday his determination to stay on for a third consecutive term -- or at least until he has crushed the insurgency

"I will never give up the nomination for the post of prime minister," he said in a statement issued by his office.

He framed the debate over his future in democratic terms, reminding Iraqis that the voters handed his bloc the most seats in parliament, and declaring that he must "stand by them during this crisis that Iraq is passing through."

Al-Maliki said that to pull out now "while facing terrorist organizations that are against Islam and humanity would show weakness instead of carrying out my legitimate, national and moral responsibility."

"I have vowed to God that I will continue to fight by the side of our armed forces and volunteers until we defeat the enemies of Iraq and its people," he said.

Iraq's military claimed progress in that fight Friday, saying troops backed by tanks and helicopter gunships captured the village of Awja -- the birthplace of former dictator Saddam Hussein -- south of Tikrit. The push through Awja is part of an offensive whose ultimate aim is to retake Tikrit.

Military spokesman Lt. Gen. Qassim al-Moussawi said 50 militants were killed in the fighting. The toll could not be independently verified.

North of Tikrit, government airstrikes hit around eight vehicles carrying militants trying to capture Iraq's largest oil refinery, said Sabah al-Nuaman, the spokesman for Iraq's counterterrorism services. He reported as many as 30 insurgents were killed.

Fighters from the Islamic States of Iraq and Syria/Levant group have been trying for weeks to capture the Beiji facility, some 155 miles north of Baghdad. The group appeared on the verge of taking the refinery last month, but military troops managed to hold on and have since received reinforcements.

Al-Nuaman also said a helicopter gunship attacked a house in the town of Qaim near the Syrian border where a gathering of the Islamic State group's local leaders was taking place. He said there were several casualties.

The militants seized Qaim, which controls a border crossing with Syria, last month. They now hold a vast stretch of territory straddling the border between the two countries.

The ISIS group is led by an Iraqi known as Abu Bakr al-Baghdadi, who this week declared the establishment of an Islamic state, or caliphate, in the land the extremists control.

In Syria, where al-Baghdadi's fighters have thrived amid the country's civil war, the group seized the al-Tanak oil field Friday near the border as they try to consolidate their hold along the length of the Euphrates River stretching through Syria and Iraq, according to the Britain-based Syrian Observatory for Human Rights.

The seizure followed the ISIS takeover of Syria's largest oil field on Thursday. Both oil fields were taken from other rebel groups.

Also Friday, more than 40 Indian nurses who were trapped in territory captured by al-Baghdadi's group were released and crossed into Iraq's largely autonomous Kurdish region, authorities said.

They will be flown to India on an aircraft arranged by their government, said Oommen Chandy, chief minister of India's Kerala state.