BBC will make a statement on Wednesday about the latest wave of redundancies, to be phased over two years.
More job two go at BBC
Last Monday, the BBC said it would cut about 200 websites and up to 360 posts from its online division as part of a plan to reduce its budget by £34m .
Among the websites set to close are teen services Switch and Blast, and the 606 football forum.
The corporation said the changes were intended to make its website more distinctive, and to reduce competition with commercial sites.
The BBC World Service is to close five of its language services.
It is thought that about 650 jobs will be lost from a workforce of some 2,400. It is believed staff will be informed on Wednesday of the redundancies. The Macedonian, Albanian and Serbian services will be axed, as will English for the Caribbean and Portuguese for Africa, in a bid to save £46m a year.
The BBC said it had to make savings after its government support was cut, but unions called the move "ferocious".
Last October, the government announced the BBC would take over the cost of the World Service from the Foreign Office.
The service, which started broadcasting in 1932, currently costs £272m a year, and has an audience of 241 million worldwide across radio, television and online.
