Former office of the Vatican's delegate to Hanoi, confiscated by the state when he was expelled in the late 1950s.

They say the large French-colonial villa and the 1.1 hectares (2.7 acre) it sits on are the former office of the Vatican's delegate to Hanoi, confiscated by the state when he was expelled in the late 1950s.

Hanoi authorities have kept the building intact but used it as a sometime discotheque while local officials have also used the garden area, shaded by an enormous banyan tree, as a motorcycle carpark, the Christians say.

"It's the land and the property of the church. We have the certificate of ownership of the property since 1933," one priest from the Hanoi archdiocese told AFP, speaking on condition he not be named.