The BBC's director general Mark Thompson will say the corporation should "think carefully" about the size of its news operation given the scale of the economic pressures faced by newspapers.
Thompson will use a speech at the Royal Television Society in London on Wednesday to say that the "multiple threats that freedom of speech and good journalism faces around the world" were the "most negative and most disturbing developments" of his time in charge of the BBC.
"The economic pressures that face print journalism in almost all developed countries are an important and complex topic in themselves, and one that I don't propose to cover in detail this evening," Thompson will say.
"Except to say that I do think it is incumbent on a free-to-air broadcaster like the BBC to think carefully about the boundaries of what it offers the public, especially in digital environments, given the scale of the challenge faced by our colleagues in print."
The extent of the BBC's online news operation has come in for criticism from its commercial rivals who have sought to launch or expand their own services online.
A particularly vocal attack came from James Murdoch, delivering his now infamous MacTaggart lecture in 2009, in which he said the BBC news operation was "throttling" the market.
A BBC source said Thompson's speech was not a precursor to sweeping changes to the corporation's online activities but a reflection of what it had already done.
"This is about us having put our house in order, not an indication of changes that are to come," said the source.
"This is not a Trojan horse, it is merely saying what we already knew, that the BBC has to be mindful about going into areas where it should not be going at the risk of being too commercially aggressive."
It said half of its websites would be cut following criticism by the BBC Trust of the lack of editorial oversight in its online division.
Separately, Thompson will outline further details of a "sustained attack" by the Iranian authorities on the BBC Persian service, which it says has 6 million listeners.
"It now looks as if those who seek to disrupt or block BBC Persian may be widening their tactics," he will say.
"There was a day recently when there was a simultaneous attempt to jam two different satellite feeds of BBC Persian into Iran, to disrupt the service's London phone lines by the use of multiple automatic calls, and a sophisticated cyber attack on the BBC.
"It is difficult, and may prove impossible, to confirm the source of these attacks, though attempted jamming of BBC services into Iran is nothing new and we regard the coincidence of these different attacks as self-evidently suspicious."
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