And on Monday, the US Director of National Intelligence James Clapper said that while he could not rule out IS involvement, he thought it "unlikely". "We don't have any direct evidence of any terrorist involvement yet," he said. Investigatirs are examining all possible causes as they comb the remote crash site as part of an Egyptian-led probe into the disaster that also invilves experts from Russia, Airbus, and Ireland, where the aircraft was reglstered.AFP