An MQ-1 Predator prepares to land while another Predator taxis across the taxiway at Joint Base Balad, Iraq, in this Jan. 2009 photo.

WASHINGTON — The Pentagon has begun flying armed aircraft over Iraq, and is preparing to deliver hundreds of air-to-ground missiles to the Iraqi security forces as they struggle to dislodge Sunni militants who overran large areas of the north and west of the country.

The moves come as Iraq’s embattled army is trying to regain the offensive against Sunni militants, including the al-Qaida-inspired Islamic State of Iraq and the Levant, who seized the country’s second largest city Mosul and Saddam Hussein’s hometown Tikrit in a lightning offense.

The Reuters news agency reported that Iraqi helicopters Friday fired on a university campus in Tikrit. Iraqi officials said they had rushed more troops to the strategic Beiji oil refinery, the scene of heavy fighting with ISIL militants.

In the wake of insurgent gains, the U.S. military has been conducting 30 to 35 intelligence, surveillance, and reconnaissance flights per day over Iraq using manned and unmanned planes. Until recently, those aircraft had been unarmed, according to U.S. officials.

But about 140 American troops arrived in Baghdad this week to form assessment teams and set up a joint operations center, and the Pentagon decided to enhance its airpower capabilities to protect those forces.

“We continue to fly both manned and unmanned aircraft over Iraq…predominantly for reconnaissance purposes,” Pentagon Press Secretary Rear Adm. John Kirby told reporters Friday. “The reason that some of those aircraft are [now] armed is primarily for force protection reasons now that we have introduced into the country some military advisors whose objective will be to operate outside the confines of the embassy.”

In addition, the military has begun arming the planes in case President Barack Obama orders airstrikes against ISIL.

“I would also tell you that we get paid to plan and prepare. The president has made no decisions about the use of kinetic force in Iraq, but it would be irresponsible for us not to be planning and preparing and thinking and to be ready in case he should make that decision,” Kirby said.

The Iraqi government has called on the U.S. to bomb ISIL fighters. But U.S. officials have said more intelligence gathering was needed before the military would be able to effectively carry out such attacks. Obama has indicated that airstrikes are an option.

In addition to the overflights, the U.S. will deliver 200 additional Hellfire air-to-ground missiles to the Iraqi security forces in mid-July, and another 600 by the end of July. The U.S. has already provided 300 Hellfires to the Iraqi government so far this year.

The Iraqis have requested another 800 Hellfires beyond the ones that are scheduled to be delivered next month, as well as small arms, Kirby said. Kirby said the requests are being processed.

Kirby pushed back against Iraqi complaints that the U.S. is holding up the delivery of F-16 fighter aircraft to the Iraqi government. Iraqi Prime Minister Nouri al-Maliki has said he wants to buy Russian jets fill the void.

The first two F-16s purchased by the Iraqi government were scheduled to be delivered in September.

“We’re still committed to the sale,” Kirby said. “And the process continues to churn, even given the unrest in Iraq.”

Still, Kirby acknowledged that preparations for the F-16 deliveries have been affected by ISIL territorial gains, which forced U.S. contractors to evacuate Balad air field.

Obama has authorized the deployment of up to 300 American military personnel to Iraq to assess the situation on the ground, including the state of the Iraqi security forces and the activities of ISIL. There are about 180 advisers on the ground now, including special operations forces. Kirby said that force level will remain the same until further assessments are made about the future of the advisory mission.

The U.S. military on Thursday named a two-star general and Iraq War veteran to oversee the advisory teams. Army Maj. Gen. Dana J.H. Pittard, deputy commanding general of operations for the Kuwait-based U.S. 3rd Army, will direct the work of the advisers. Pittard served as a brigade commander during the Iraq War and later commanded the Iraq Assistance Group, which managed the transition to Iraqi security control.

As the U.S. bolsters its support, Iraq’s army has reinforced its troops holding out against ISIL militants at the Beiji oil refinery, which supplies about 25 percent of the country’s domestic fuel needs. An Iraqi official told reporters that about 200 troops had joined a 100-strong contingent that has been fighting for more than a week around the refinery.

State-run television aired footage Friday purporting to show troops disembarking from helicopters at Beiji, with some carrying boxes of supplies. Dense black smoke was rising from what appeared to be a large fuel tank.

In the west, ISIL fighters clashed with a joint force of Iraqi Army and tribal forces in Barwana, eight miles south of the Haditha dam. Government forces are said to be reinforcing the dam to prevent a repeat of an incident earlier this year when the ISIL seized the Fallujah dam on the Euphrates River. The ISIL opened the floodgates, inundating surrounding areas and depriving downstream communities of water.

In London, Human Rights Watch said Friday that analysis of photographs and satellite imagery “strongly indicate” that the ISIL staged mass executions in Tikrit after capturing it on June 11. Human Rights Watch estimated that as many as 190 men were slaughtered over three days but the real figure may be higher because an on-site investigation is not possible.

The massacre appeared to be aimed at instilling fear in Iraq’s demoralized armed forces as well as among the country’s Shiite majority, whom the Islamic State views as heretics.

During its offensive, the ISIL was helped by Sunni tribes and former members of Saddam’s Sunni-dominated Baath Party, who have long complained they were marginalized by al-Maliki’s Shiite-led government. U.S. officials, meanwhile, have urged the Iraqis to form an inclusive government to wean Sunnis away from the ISIL.

Al-Maliki’s party won the most seats in the April parliamentary election but needs support from other parties to gain a parliamentary majority and to hold onto his job. Parliament is due to meet Tuesday to begin the process of picking the next prime minister, with the ISIL threat adding new urgency to finish the process soon. Many Sunnis and some Shiite politicians believe al-­Maliki must be replaced because of his image as a polarizing Shiite hard-liner.

On Friday, Iraq’s top Shiite cleric, Ayatollah Ali al-Sistani, stepped up pressure on parliament, calling on political blocs to agree on the next prime minister even before parliament convenes.

Al-Maliki, who is fighting to keep his job, warned army commanders that militants were likely to try to undermine security in the Iraqi capital ahead of Tuesday’s session. “Baghdad must be secured and not subjected to any instability at this time,” he said in televised comments.

harper.jon@stripes.com

Twitter: @JHarperStripes