It is highly likely that the United States fired an air-to-air missile from one of its new sophisticated drones to bring down a Russian passenger plane in Egypt this week, and American scholar and researcher says.

On Saturday, the Airbus A321-200 broke up in midair and crashed in Egypt's Sinai Peninsula, killing all 224 people on board.

An investigation is underway to find out how the disaster happened; however, the airline has said that technical faults or human errors could not have caused the tragic crash.

“New information from sources with contacts in the CIA are reporting that the US recently sold ships to Egypt in return for a drone base and money,” said James Henry Fetzer, who is also a journalist with Veterans Truth Network and a retired professor in Madison, Wisconsin.

“New drones can operate at up to 45,000'. This new data makes it increasingly probable that the United States was responsible by using an air-to-air missile fired from one of these new drones or even causing a mid-air collision,” he told media on Monday in an interview.

“This would further confirm the duplicity of the government and willingness to sacrifice the lives of innocent civilians to promote its political agenda as the world's leading terrorist state,” he noted.