(CNN) - The U.S. intelligence community now believes two key terrorist operatives targeted by the United States in the opening night of attacks in Syria are still alive and could be actively plotting, multiple officials tell CNN.
The operatives are key members of Khorasan Group, the al Qaeda affiliate entrenched in Syria that the United States has declared poses a great risk to American national security. One official with direct knowledge of the latest U.S. assessment said the working assumption now is that both Muhsin al-Fadhli, the leader of the group, and David Drugeon, a French jihadist and key member, who is believed to be a skilled bomb-maker, are alive. The United States does not know with certainty if they are injured.
An intelligence analyst with knowledge of the intelligence tells CNN "its 99.5% certain" they are alive.
The Syrian terror group al-Nusra Front says that its leader has been killed by a U.S. airstrike.
A statement from the group says Abu Yousef al-Turki was killed overnight in U.S.-led airstrikes in Syria. CNN cannot independently verify al-Nusra's claims, but the Syrian Observatory for Human Rights, a monitoring group, says the group was among those targeted during the airstrikes.
Former U.S. Ambassador to the United Nations for Management and Reform, Mark Wallace, is OutFront. Wallace has just launched the counter extremism project, a not-for-profit group working to expose and disrupt sources of funding for extremist groups.
Below, CNN Terrorism Analyst Paul Cruickshank and CNN Military Analyst Retired Colonel Peter Mansoor give their takes on the airstrikes
The U.S. is on a heightened state of alert after the Department of Homeland Security warned of lone-wolf attacks in response to airstrikes on Syria.
This comes as the Pentagon says Monday night's airstrikes targeted not just ISIS but perhaps an even more immediate threat to the U.S. homeland called Khorasan.
According to a U.S. official, Khorasan, an al Qaeda-linked organization, was ready to blow up commercial flights.
CNN's Deborah Feyerick is OutFront with details.
Below, White House Deputy National Security Adviser Tony Blinken weighs in on the attacks.
(CNN) - The Islamic State terror group is now "a credible alternative to al Qaeda" that is "expanding its presence" with foreign fighters returning from Syria, and possibly Iraq, to their home countries, a U.S. intelligence official said Thursday.
The official, who declined to be identified due to the sensitive nature of the information, has direct knowledge of the latest intelligence on the group, also known as ISIS or ISIL.
According to an assessment, the group has grown in size since the spring and its takeover of Mosul in northern Iraq as more fighters from around the world have mainly traveled to Syria to join its ranks.
The United States believes that while the group remains largely focused on its brutal takeover of large areas of Iraq, there is also an "expansion of its external terrorist ambitions."
United States officials are tying the new threat of shoe bombs on airplanes to al Qaeda.
There are indications that the threat could ultimately be tied to Ibrahim al Asiri, the master bomb-maker for al Qaeda in the Arabian Peninsula.
He's the man officials say designed the underwear bomb that failed to detonate aboard a Detroit bound flight on Christmas Day in 2009.
He also built the printer-cartridge bombs that al Qaeda placed on cargo planes destined for Chicago the following year.
Al Qaeda link to shoe-bomb warning
An official tells CNN the new warning is related to recent intelligence gathered on bomb-making tactics believed tied to Asiri.
CNN's Erin Burnett talks to National Security Analyst and Former CIA operative Bob Baer about the latest threat and why Asiri hasn't been caught.
"He's up in the mountains of Yemen," Baer says. "There's no digital footprint that he's left behind. He's read about leaks in this country. He's fairly immune and there's nothing the Yemeni government could do about it."