KIEV, Jan 8 (Reuters) - Ukraine's embassy in Iran dropped an initial reference to engine failure as the cause of a Ukrainian plane crash outside Tehran on Wednesday.
It said in a second statement that the causes had not been disclosed and that any previous comments were not official.
Asked at a briefing in Kiev if the plane could have been downed by a missile, Ukraine's Prime Minister Oleksiy Honcharuk cautioned against speculation until the results of an investigation were known.
He also said that Ukraine had banned flights through Iranian airspace by its airliners from Jan. 9.
Reporting by Pavel Polityuk and Natalia Zinets; writing by Matthias Williams