U.S. President Barack Obama says his priority is rolling back the gains the Islamic State has made in Iraq.
The president spoke to reporters at the White House Thursday, moments before meeting with his national security team on the crises in Iraq and Syria.
Obama said the United States is continuing with its targeted strikes on Islamic State targets in Iraq, saying such actions have caused it to lose arms and equipment.
The president, however, said beyond that, he does not have a strategy yet in dealing with the militants, countering speculation that airstrikes on Islamic State targets in Syria may be imminent.
The president said Islamic State has found a haven in Syria and that Syrian forces cannot get in areas under its control.
He said outsiders have to stop backing Islamic State and that others in the region have to recognize the threat the militants pose to them.
Obama last week authorized air surveillance on Islamic State militants in Syria.
Syria said this week it would welcome U.S. and British help in fighting the militants, but only in coordination with Damascus. It says a unilateral U.S. attack would violate its airspace and could lead to an attempt to shoot down American warplanes.
U.S. officials say they would not first consult Syria, saying President Bashar al-Assad has lost the authority to lead.
The White House gave no information on Obama's meeting with his national security team Thursday other than to say there will be more meetings in the coming days.
Meanwhile, The Washington Post newspaper reports that at least four Western hostages held by the Islamic State in Syria were waterboarded.
The paper said they included James Foley, the American journalist who was beheaded by an Islamic State militant.
The Post cited people with firsthand (direct) knowledge of what happened to the hostages.
Waterboarding is a form of torture that simulates drowning. The U.S. Central Intelligence Agency used the interrogation method on terror suspects arrested after the September 11 attacks in 2001.
Second American killed fighting for IS
Meanwhile, a Somali-American man is reported to be the second U.S. national killed while fighting alongside militants in Syria.
TV station KSMP in Minneapolis, Minnesota, has identified the man as Abdirahman Muhumed, who left the area to fight for the Islamic State group, also known as IS.
According to its sources, the station said Muhumed died in the same battle as Douglas McCain, 33, also from the Minneapolis area. His death this weekend in Syria was confirmed by the U.S. National Security Council earlier this week.
The two men apparently knew each other.
In its coverage of McCain's death, Minnesota Public Radio had reported that his Facebook page indicated he knew Muhumed, "a Minneapolis man who went to Syria and joined the Islamic State."
Muhumed had posted a photo of himself holding a rifle and a Qur'an, eliciting negative responses from Facebook "friends," MPR said. But McCain, in a Feb. 19 post, encouraged Muhumed to "continue protecting our brothers and sisters."
Minneapolis, in the northern state of Minnesota, is home to a large Somali-American community. More than a dozen young men have left the community to fight in Syria, drawn by Islamic radicalism.
The FBI already was investigating the death of McCain, who had been on a watch list given his overseas travel and the content of his social media posts. The bureau's field office in Minneapolis for almost a decade has looked into the cases of several young Somali-Americans joining the terrorist group al-Shabab in Somalia.
E.K. Wilson, spokesman for the field office, told The Associated Press: "We have done extensive outreach recently, as we have the last seven years, but we've had a concerted effort ... over the last few months" involving travel to Syria.
Reports of a second American killed in Syria began circulating on social media sites Wednesday. The council said late in the day it was aware of the reports, but was not in a position at the time to say whether they were true.
Mother pleads for son's life
Meanwhile, the mother of an American journalist being held by Islamic State militants has pleaded with the group's leader to let her son, Steven Sotloff, go free.
In a video released Wednesday, Shirley Sotloff said he is an "honorable man" who should not be punished for U.S. government actions.
"I've learned that Islam teaches that no individual should be held responsible for the sins of others," she said. "Steven has no control over the actions of the U.S. government. He is an innocent journalist. I've also learned that you, the Caliph, can grant amnesty. I ask you to please release my child."
The IS group beheaded American journalist James Foley earlier this month and is threatening to kill Sotloff if the United States does not stop carrying out airstrikes on militants in Iraq.
White House spokesman Josh Earnest said Obama administration officials have been in contact with the Sotloff family, but he did not give specifics on what advice the family was given on the "wisdom" of releasing the video.
"As you know, this administration is deeply engaged and doing everything we can to seek the return of every American who is currently being held in that region," Earnest said.
Also Wednesday, Peter Theo Curtis, another American journalist who had been held hostage by Syrian militants for two years, said he was "overwhelmed with emotion" after learning how many people across the world had worked for his release.
Curtis also expressed gratitude for the many people who have welcomed him back to the United States since his return this week.