The BBC World Service is to close five of its language services with hundreds of job losses expected.
It is thought about 650 jobs will be cut from a workforce of some 2,400 in a bid to save £46 million a year.
Union leaders said the “ferocious cuts” were a “direct result of the Government slashing funding to an internationally respected and successful broadcaster”.
The Corporation said in a statement: “BBC World Service has announced that it will be closing five language services – Albanian, Macedonian, Portuguese for Africa and Serbian; as well as the English for the Caribbean regional service.
“This is part of its response to a cut to its Grant-in-Aid funding from the UK’s Foreign and Commonwealth Office.
“The cut is part of a BBC World Service restructure in order to meet a 16% savings target announced in the Government’s spending review of October 20 last year.”
BBC Global News Director Peter Horrocks said: “These closures are not a reflection on the performance of individual services or programmes. They are all extremely important to their audiences and to the BBC.
“It is simply that there is a need to make savings due to the scale of the cuts to the BBC World Service’s Grant-in-Aid funding from the UK’s Foreign and Commonwealth Office and we need to focus our efforts in the languages where there is the greatest need and where we have the strongest impact.”
The BBC said it would not confirm details of job losses before briefing staff.
Mr Horrocks is due to hold a press conference at the World Service headquarters in central London where he will give “significant details” of the service’s response to funding cuts.