AT least 12 people, including four journalists and a senior think tank analyst, have been barred from flying to Tigray, four of the passengers said after Ethiopian security officials said the region's elections later this week were illegal. Ethiopia's upper house said on Saturday plans by the Tigray region to hold an election on September 9 for regional parliament and other positions were unconstitutional, setting up a potential clash between the central government and the powerful Tigray People's Liberation Front. The TPLF, which runs the northern province, has said the vote will go ahead despite pressure from the central government.…