President Barack Obama signaled the U.S. has no immediate plans to escalate military operations against Islamic State extremists in Iraq or Syria, stressing the need to counter the group’s advance while formulating a broader strategy to protect U.S. interests and allies.
Mr. Obama spoke on a day when Syrian opposition activists said the Sunni radical group had killed nearly 500 people since Sunday in the northeastern province of Raqqa, most of them Syrian troops captured on an air base seized by Islamic State fighters.
The president, who met with his national security team Thursday afternoon, said the U.S. is still developing its plan to root Islamic State out of Iraq and Syria, where it has captured large swaths of territory since June.
“We don’t have a strategy yet,” Mr. Obama said of potential plans for airstrikes in Syria. He said the long-term blueprint to respond to the growth of the militant group, also known as ISIS or ISIL, can’t depend on U.S. actions alone.
“Rooting out a cancer like ISIL will not be quick, or easy, but I’m confident that we can and we will, working closely with our allies and our partners,” Mr. Obama said.
The president walked back reports suggesting there may be an immediate escalation of military operations, including potential airstrikes in Syria.
“We need to make sure that we’ve got clear plans so we’re developing them,” he said. He said he was more focused on military activity in Iraq and the need for a unified government in Baghdad to help combat militant forces. “My priority at this point is to make sure that the gains that ISIL made in Iraq are rolled back and that Iraq has the opportunity to govern itself effectively and secure itself,” Mr. Obama said.
Ultimately, the U.S. is focused on a strategy to create an international coalition to “systematically degrade ISIL’s capacity to engage in the terrible violence and disruptions that they’ve been engaging in.”
The president’s comments hastened calls from U.S. lawmakers for the Obama administration to outline its strategy for combating the threat posed by Islamic State.
A spokesman for House Speaker John Boehner (R., Ohio) said “the fact that the president admitted he doesn’t have one should alarm every American.”
Senate Minority Leader Mitch McConnell (R., Ky.) said it’s imperative for Mr. Obama “to use the full extent of his authorities to attack this enemy force.”
While a series of airstrikes on Islamic State targets in Iraq and humanitarian-aid drops thus far conducted by U.S. forces have had some success in blunting the progress of the fighters, a longer-term strategy needs to be outlined publicly in order to unite the public, Sen. Bob Casey (D., Pa.) said before Mr. Obama spoke.
Following the speech, the White House clarified Mr. Obama’s remarks about strategy. “The president was asked a specific question about possible military action in Syria against ISIL, and he was explicit that he is still waiting for plans that are being developed by the Pentagon for military options against ISIL in Syria,” White House Press Secretary Josh Earnest said. “But when it comes to confronting ISIL in Iraq, the president has been very clear for months about what our comprehensive strategy is.”
There have also been increasing calls from Republicans and Democrats for Mr. Obama to seek congressional approval for any escalation of military operations in the region.
Mr. Obama said he would continue to consult with Congress, but insisted that the current operations in Iraq fall under his authority as commander in chief. He said the administration would continue to discuss plans with lawmakers and allowed that “it’ll be important for Congress to weigh in.”
“I will consult with Congress and make sure that their voices are heard,” Mr. Obama said.
Videos and photographs purporting to show militants killing captured soldiers were posted on social-media websites Thursday. The soldiers were captured when the group took over Tabqa air base on Sunday, giving them control of all of Raqqa—the first Syrian province to come entirely under Islamic State rule.
The U.K.-based Syrian Observatory for Human Rights, an opposition group tracking the conflict through a network of activists inside Syria, said 160 captured soldiers have been killed since Wednesday. They were among 490 people in Raqqa killed since Sunday, most of them Syrian troops, according to four opposition activists.
None of the reports could be independently verified.
The accounts of the killings came from an activist in Raqqa who witnessed the aftermath with the consent of Islamic State. Other activists operating from the Syrian border with Turkey were in contact with Islamic State militants and Raqqa residents.
In one video, a column of dozens of men identified as soldiers and officers are shown in their underwear being herded through the desert by militants.
Some of the fighters are on foot and others in an accompanying convoy of armed pickup trucks and SUVs. They occasionally hit their captives with the butts of their rifles or forced them to chant in praise of Islamic State.
The Islamic State has drawn foreign fighters into its campaign in Syria and Iraq and some of those who spoke on the videos had accents from various parts of the Middle East.
“Come on like sheep,” says a male voice, who appears to be the videographer in one of the cars, as he laughs and taunts the prisoners. The man spoke with a Gulf Arab accent.
Another video shows men motionless in their underwear lined up face down in a long row in a desert area after their purported killings. Some bodies appear to be piled on the side. Men speaking with a North African accent are heard on this video.
The videos are likely to further enrage supporters of Syrian President Bashar al-Assad, especially members of his Alawite minority who are the backbone of the regime’s forces. Many of those supporters are already blaming military leaders for surrendering the air base to Islamic State, also known as ISIS.
Some Assad regime supporters expressed their rage Thursday on a Facebook page titled “Eagles of the Tabqa Air Base” set up to pay tribute to the soldiers taken captive by Islamic State and to share news of their fate. A posting by the page’s administrator assails state media for completely ignoring the news. It calls military leaders “traitors for leaving them prey to ISIS monsters.”
There was no immediate comment from Syrian officials on the purported killings.
A third video shows militants interrogating a group of regime soldiers at what activists said was an Islamic State training camp and detention center called Al-Ekershi east of the city of Raqqa, the provincial capital.
“You are a lieutenant colonel, an Alawite right?” asks a man behind the camera and speaking with a Tunisian accent. A middle-aged man in torn military fatigues nods his head. “Why are you fighting for the tyrant? Why are you fighting for Bashar?” asks the man behind the camera.
On the same video, a group of men, some in their underwear, sit on the floor in the corner as they are being cursed at and beaten by men speaking with Syrian accents. At the end of the video, the man with the Tunisian accent is heard telling the colonel: “We are going to send you to hell, God willing, we are going to slaughter you.”
The Syrian regime began conducting airstrikes against Islamic State positions in June, but clashes on the ground have been limited. Regime forces are overstretched and weakened by more than three years of civil war and are focusing limited resources on battling rebels around Damascus and the strategic corridor that links the capital with the western coast through the central province of Homs.
The regime’s strategy now hinges on the hope that the West and regional powers will be so horrified by Islamic State’s actions that they will stop backing rebels in their quest to topple Mr. Assad and instead focus on rolling back the threat of the extremist group.