'The Turk' taken out: Al Qaeda-linked terror group says leader killed in Syria airstrikes

(CNN) -- The United States is doing what it must to "take the fight to terrorists," leading a coalition of Arab nations in a series of airstrikes against the so-called Islamic State terror group in Syria, President Barack Obama said Tuesday.

At the same time, the United States took action -- on its own -- against another terrorist organization, the Khorasan Group. Obama described its members as "seasoned al-Qaeda operatives in Syria."

U.S. officials said the group was plotting attacks against the United States and other Western targets.

The plots against the United States were discovered by the intelligence community in the past week, an intelligence source with knowledge of the matter told CNN. The source did not say what the target may have been, but said the plot potentially involved a bomb made of a nonmetallic device like a toothpaste container or clothes dipped in explosive material.

A plot involving concealed bombs on airplanes "was just one option they were looking at," a U.S. official said.

"Once again, it must be clear to anyone who would plot against America and try to do Americans harm that we will not tolerate safe havens for terrorists who threaten our people," Obama said in televised remarks from the White House.

Concern over a possible backlash by the terror groups has prompted the U.S. Department of Homeland Security to issue a bulletin warning law enforcement agencies to be on heightened alert for lone-wolf terror attacks on U.S. soil in wake of the airstrikes, a U.S. law enforcement official with knowledge of the warning told CNN.

Terror group: 'Turk' is dead

The airstrikes, meanwhile, appear to have taken a toll on another terror group, killing the leader of the al Qaeda-linked al-Nusra Front, according to a statement released by the group. It identified the leader as Abu Yousef al-Turki, also known as "The Turk."

The al-Nusra statement posted on Twitter was accompanied by a so-called proof-of-death -- a photograph -- of the former fighter.

CNN cannot independently verify al-Nusra's claims, but the monitoring group the Syrian Observatory for Human Rights reported the terror group was among those targeted during the airstrikes. The United States has not identified al-Nusra as a group targeted in the strikes.

The airstrikes that began early Tuesday morning local time "were only the beginning," Pentagon spokesman, Navy Rear Adm. John Kirby, said. He declined to comment about future military operations.

Bahrain, Saudi Arabia, the United Arab Emirates and Jordan took part in airstrikes on ISIS targets, the U.S. military said. Qatar played a supporting role, the U.S. military said.

Saying he "made clear that America would act as part of a broad coalition," Obama said: "That's exactly what we've done."

"The strength of this coalition makes it clear to the world that this is not America's fight alone," the President said.



Obama met hours later with officials from the five Arab nations who make up the coalition. There was an a strong agreement that "the campaign against ISIS was a long-term one and they were all in it for the long haul," a senior State Department official with knowledge of the meeting said.

"Everyone at the table agreed there are times in the world when you need to take a stand," the official said on condition of anonymity.

But Syria warned the United States not to repeat the "American fiasco in Iraq by undertaking the same kind of blind military attacks," Bashar Ja'afari, Syria's ambassador to the United Nations, told CNN.