Rep. Ed Royce: 'Highly Likely' Terror Behind EgyptAir Flight 804 Crash

It is "highly likely" terror is the leading theory to what brought down EgyptAir Flight 804, Chair of the House Foreign Affairs Committee Rep. Ed Royce said on Sunday.

"In my view, it's highly likely because of the amount of effort that ISIS and Al Qaeda have put over the last few years into trying to develop an undetectable bomb," Royce said on "This Week," "and this is one of the concerns we've had about allowing ISIS to operate in Raqqah, with their facilities to try to develop that-- those-- that type of bomb technology."

"The same is happening with Al Qaeda in the Middle East," he said.

But the ranking member of the House Permanent Select Committee on Intelligence, Rep. Adam Schiff, is "not convinced" that terror is the leading theory.

"I'm not convinced. I think it started out certainly as our main suspicion," Schiff said on "This Week." "But here we are, we have examined the overhead images. We've looked at the signals intelligence, we've looked at the manifest, we have not come up with any hard evidence of terrorism, as of yet."

The missing EgyptAir plane was en route to Cairo from Paris when it disappeared early Thursday with 66 people aboard. According to the company, the Airbus A320 lost contact with the radar tracking system at 2:45 a.m. at an altitude of 37,000 feet.

Schiff added that it is "very suspicious" that ISIS has not claimed responsibility, four days after the EgyptAir Flight Air.

"If it was ISIS -- and it's still very possible -- I think it's more likely to have been a lone actor that wasn't operating with the command and control of Raqqah, taking matters into their own hands," Schiff said.