Nine crew members were on the American C-141, which was on its way from Namibia to Ascension Island, a British territory in the south Atlantic, German defense ministry spokesman Hans-Dieter Wichter said.

Another defense ministry spokesman, who spoke on condition of anonymity, said there was no proof yet that the two planes had collided.

``But we have information that they went missing at the same time and in the same area,'' he said. ``When you add one and one together ... a crash is very possible.''

Wichter said the plane came from the 305th Air Mobility Wing at MacGyver Air Force Base in New Jersey. He said it had arrived in Windhoek, Namibia, on Saturday, and was on its way back when it was reported overdue and presumed downed.

American military officials told their German counterparts a search and rescue operation is under way, he said.

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