BEIRUT (AP) — Kurdish-led Syrian fighters pushed ahead Monday with an offensive aimed at isolating and encircling the Islamic State group's stronghold of Raqqa, making small advances in villages north of the extremists' de facto capital.
Warplanes from a U.S.-led coalition provided air cover for the fighters from the Syria Democratic Forces, an alliance of Kurdish and Arab fighters formed last year with the aim of incorporating non-Kurdish elements into the mainly Kurdish militia fighting IS in Syria.
The SDF announced the start of the campaign to liberate Raqqa at a news conference Sunday in northern Syria, and the United States, France and Britain said they would provide air support for the offensive, dubbed "Eurphrates Rage."
But the battle for the Syrian city, home to nearly 200,000 mostly Sunni Arabs and an estimated 5,000 IS militants including many foreigners, could be long and costly.
IS fighters are expected to fight until the end, considering that losing Raqqa would mean the extremist group would not fully control any large cities in Syria, where a civil war has been raging for more than five years.
At the same time, Iraqi forces are pushing forward against Mosul, Iraq's second-largest city and the militants' biggest urban stronghold in that country.
SDF fighters needed more than two months earlier this year to capture the Syrian town of Manbij, which is far smaller than Raqqa.
Raqqa has been under IS control since early 2014 and is home to some of the group's top leaders. It has been the extremists' self-styled capital since they declared a caliphate in areas they captured that year in Iraq and Syria.
The U.S. commander of coalition forces fighting IS said the Raqqa operation is aimed at eventually cutting off the extremists from Mosul, where U.S.-backed Iraqi forces have entered the city's eastern outskirts amid fierce resistance.
Lt. Gen. Stephen J. Townsend said the Arab element of the SDF is "indigenous to the area" and will help establish "regional support" for SDF operations. His comments appeared to be aimed at soothing concerns that Kurdish forces would take over the predominantly Sunni Arab city.
A spokeswoman for the Raqqa campaign said the SDF as a whole is half-Arab and half-Kurdish, but the 30,000 troops fighting in the Raqqa campaign are 80 percent Arab. Many in Syria are wary of those figures, and they fear that the Kurds are aiming to carve out an autonomous state in Syria.
The activist media group that calls itself Raqqa is Being Slaughtered Silently, which was originally formed to smuggle information out of Islamic State territory, says the SDF is 80 percent Kurdish.
Unlike other successful military efforts to drive Islamic State out of cities in Iraq, the Raqqa offensive faces several political obstacles.
In Iraq, the U.S.-led coalition is working with the government in Baghdad, but Washington and its partners in Syria rely on a mixture of Arab and Kurdish opposition groups, some of which are bitter rivals. Tensions are exacerbated by Russian and Syrian forces on one side and Turkish-backed forces on another.
On Monday, President Recep Tayyip Erdogan reiterated Turkey's opposition to the use of Syrian Kurdish fighters against the Islamic State group. Turkey views the U.S.-backed Syrian Kurdish militia, the People's Protection Units, or YPG, and its political wing as terrorist organizations.
Erdogan did not make a direct reference to the Raqqa operation but said "no one in the world will buy this naïve attitude (of attacking) Daesh with another terror organization," using an Arabic acronym for the Islamic State group.
In Moscow, Stanislav Ivanov of the Institute of the World Economy and International Relations, a government-funded think-tank, said the Kurdish-led offensive on Raqqa reflects the Kurds' push for creating their own state and winning a stake in future peace talks.
"The 40 million Kurdish people would never abandon their push for creating their own state," Ivanov said in remarks carried by the state news agency Tass.
He said the Kurds would probably refrain from entering the city and would limit themselves to controlling access to it.
"It's not part of the Kurds' plan to engage in fighting with the Sunni Arab majority of Raqqa," he said. "Their goal in Syria is to protect their enclaves in the north."
A Kurdish official with the Raqqa campaign said the SDF had so far liberated a stretch of 15 kilometers (about 9 miles) south of the Kurdish-controlled town of Ein Issa. The official spoke on condition of anonymity because he was not authorized to talk to reporters.
The Britain-based Syrian Observatory for Human Rights also said heavy fighting was underway north of Raqqa.
The U.S. Central Command said coalition aircraft conducted 16 airstrikes Sunday north of Raqqa, mostly near the area of Ein Issa, where the fighting appeared to be concentrated.
The SDF is made up of Arab, Kurdish and Turkmen groups that have captured wide areas of northern Syria from IS in the past year. The largest and most powerful groups in the coalition are the main Kurdish militias known as the People's Protection Units, or YPG, and the Women's Protection Units, or YPJ.
Fayad al-Ghanem, the commander of the small Arab Raqqa Hawks Brigade group, said in an online video that their aim is to besiege Raqqa and liberate villages and towns around it.
"We want to rescue the people from the injustice of Daesh," al-Ghanem said.
SDF said its fighters destroyed a vehicle rigged with explosives on a farm north of Raqqa.
The IS-linked Aamaq news agency said IS militants hit an SDF armored vehicle with a missile, killing everyone inside. It later reported that IS fighters destroyed six SUVs for the SDF with missiles, killing seven fighters.
Associated Press writers Philip Issa in Beirut, Susan Frazer in Ankara, Turkey, and Vladimir Isachenkov in Moscow contributed.