Did ISIS shoot down the Russian airliner on Saturday? Do they even have the ability to do so?

“It’s unlikely but I wouldn’t rule it out,” U.S. Director of National Intelligence James Clapper told attendees at the Defense One Summit on Monday in Washington, D.C. “We don’t have any direct evidence of any terrorist involvement yet. ISIL had tweeted claims.”

On Saturday, 217 passengers and seven crew members died when their A-321 passenger jet, flying from Sharm El-Sheikh to St. Petersburg, crashed in the Sinai Peninsula. The crash was the worst air disaster in Russian aviation history.

Clapper also took a moment to discuss Vladimir Putin more broadly, speculating that the Russian president, who sees himself as “a man on white horseback” riding to Syria’s salvation, will be probably be drawn into sending more troops to the war-torn country. Read that to mean more Russian boots on the ground.

“They will probably be drawn into sending more advisors,” he told attendees.

Russia began deploying special operations forces, also known as the Spetsnazovtsi or Spetsnaz, to Syria at the start of October. Some reports they were being re-deployed from Ukraine.