The cause of the Dec. 6 crash in southeastern Turkey of an Anka UAV — the first unmanned aircraft designed and built in the country — remains under investigation, military officials here said.

The UAV went down during a day flight , the officials said. The Anka has been undergoing operational test flights at a military base in Batman, southeastern Turkey.

In a written statement, Turkish Aerospace Industries (TAI), maker of the Anka, said that a technical investigation into the crash was progressing, with no results so far. In 2012, the Anka made two crash landings during flight tests. […]