President Barack Obama notified Congress on Monday that about 275 U.S. military personnel are deploying to Iraq.
Obama said the troops are going to provide support and security for U.S. personnel and the U.S. Embassy in Baghdad. He said the forces are equipped for combat and will remain in Iraq until the security situation improves and they are no longer needed.
About 160 troops are already in Iraq, including 50 Marines and more than 100 Army soldiers, some of whom have only recently arrived.
Under the authorization Obama outlined, a U.S. official said Washington will put an additional 100 soldiers in a nearby third country, where they would be held in reserve until needed.
The White House said the U.S. military personnel are entering Iraq with its consent.
The move comes after Sunni insurgents captured a key northern Iraqi town along the highway to Syria early on Monday, compounding the woes of Iraq's Shia-led government a week after it lost a vast swath of territory to insurgents in the country's north.
The town of Tal Afar, with a population of about 200,000 people, was taken just before dawn, sources in the town told Al Jazeera. The town's mix of mostly Shia and Sunni Turkomen raises the grim specter of large-scale atrocities by Sunni militants from the Al-Qaeda splinter group the Islamic State in Iraq and the Levant (ISIL), which claims to have killed hundreds of Shia in areas it seized last week.
That fear was underlined by a report that circulated Monday that ISIL insurgents a day earlier had ambushed an executed more than two dozen volunteer Shia militiamen, who answered the joint call from Shia leaders and the government to aid the country's underpowered security forces.
As Iraqi security forces prove unable to defend the country's Sunni regions from the ISIL incursion, Prime Minister Nouri al-Maliki is awaiting assistance from his main allies, the U.S. and Iran, who have both indicated they might be open to a rare joint operation against the extremist group.
U.S. Secretary of State John Kerry said Monday that the U.S. would consider "a very thorough vetting of every option that is available" — including cooperation with its longtime enemy, Iran. The possibility of drone strikes was also on the table for the U.S., Kerry told Yahoo! News.
West of Baghdad on Monday, an army helicopter was shot down during clashes near the city of Fallujah, killing the aircraft's two-man crew, security officials said.
In a sign of Iran's deepening involvement in the Iraqi crisis, the commander of Tehran's elite Quds Force has arrived to help Iraq's military and Shia militias gear up to fight the insurgents, Iraqi security officials said Monday. The presence of Iranian Gen. Ghasem Soleimani, however, is likely to fuel longtime Sunni suspicions about the Shia-led government's close ties with the region's Shia power.
A Shia-majority city of 7 million, Baghdad is not in immediate danger of falling into the hands of the Sunni fighters – but a string of bombings on Sunday killed 19 people and wounded more than 40. The violence added to the nervousness of the Iraqi capital's residents.
Security has been tightened around the city, particularly on its northern and western edges, and food prices have dramatically gone up because of the transportation disruptions on the main road heading north from the capital.
Separately on Monday, Iraq's Ministry of Communications ordered Internet Service Providers to cut off service in the five provinces where the insurgency has taken charge. The move is seen as an attempt to contain ISIL's prolific use of social media to promote its campaign and recruit new fighters to its cause.
The Iraqi Network for Social Media, an Internet advocacy group, said Monday that Internet access on cell phones had also been blocked in all provinces except the northern Kurdish regions.
Tal Afar is only 90 miles from the border with Syria, where the ISIL is fighting President Bashar al-Assad's government — as well as with other rebel factions — and controls territory abutting the Iraqi border. It lies on a main highway heading from Mosul to Syria, boosting the armed group’s drive to link areas under its control on both sides of the border.
ISIL, whose ultimate goal is to establish an Islamic caliphate encompassing modern-day Syria and Iraq, has been bolstered by its success in Syria and by widespread Sunni hostility towards Maliki, a Shia who is accused of stoking sectarianism in Iraq. According to a report from The Guardian, after looting Mosul's central bank the group now has more than $2 billion in funding.
Tal Afar's capture came just hours after Maliki, addressing volunteers joining the security forces, vowed to retake every inch of territory seized by the rebels. "We will march and liberate every inch they defaced, from the country's northernmost point to the southernmost point," Maliki said.
Over the weekend, the ISIL posted graphic photos that appeared to show their gunmen massacring scores of captured Iraqi soldiers. The pictures, on a militant website, show masked ISIL fighters loading the captives onto flatbed trucks before forcing them to lie face-down in a shallow ditch with their arms tied behind their backs. The final images show the bodies of the captives soaked in blood after apparently being shot.
Iraq's chief military spokesman, Lt. Gen. Qassim al-Moussawi, confirmed the photos' authenticity and said he was aware of cases of mass murder of captured Iraqi soldiers in areas held by the ISIL.
He told the AP that an examination of the images by military experts showed that about 170 soldiers were shot to death by the militants after their capture.
Captions on the photos showing the soldiers after they were shot say "hundreds have been liquidated," but the total numbers could not be verified.
U.N. Secretary-General Ban Ki-moon said Monday that the reports of radical fighters massacring Iraqi soldiers was "deeply disturbing," and warned in a statement against sectarian rhetoric that could inflame the conflict and carry grave implications for the entire region.
Al Jazeera and The Associated Press