Rebels from Ethiopia's northern Tigray region have taken control of the town of Lalibela, a Unesco world heritage site in neighbouring Amhara region.
Lalibela, home to 13th Century churches hewn from rock, is a holy site for millions of Orthodox Christians.
Residents have been fleeing the rebel advance, local officials told the BBC.
Thousands have been killed since war broke out last November. Fighting is now spreading into Amhara and Afar, another region bordering Tigray.
Millions of people have also been displaced.
Both the Tigray rebel forces and the Ethiopian army and its allies have been accused of committing human rights abuses and war crimes.