It was a competency based interview through the phone, in English. A panel of three was interviewing, with my potential supervisor leading the interview. It was scheduled around 10 days in advance and I received the notification within 2 weeks.
I read about the country and the project online to prepare for the interview, though the questions were not as demanding as I expected. The whole interview took approximately 25 minutes and the interviewers were very polite and patient to hear my answers.