Chancellor Angela Merkel, President Joachim Gauck and hundreds of other dignitaries and relatives of the 150 people killed in last month's crash of a Germanwings jet are gathering in Cologne's landmark cathedral to pay tribute to those who died.

Archbishop of Cologne Rainer Maria Woelki says 150 candles will be lighted in memory of each of those who died including co-pilot Andreas Lubitz, who investigators believe deliberately crashed the plane. Woelki told Bild newspaper Friday "it's not for us to judge."

Some 1,400 guests were expected for the memorial service, and flags were ordered flown at half-staff around the country as part of the tribute.

The Barcelona to Duesseldorf flight crashed on March 24.