By Sebastian Usher
BBC world media correspondent
Ukraine journalists pledge impartiality
Journalists on Ukraine's state-owned channel - which had previously given unswerving support to Prime Minister Viktor Yanukovych - have joined the opposition, saying they have had enough of "telling the government's lies".
Journalists on another strongly pro-government TV station have also promised an end to the bias in their reporting. The turnaround in news coverage, after years of toeing the government line, is a big setback for Mr Yanukovych.
Journalists in Ukraine seem to have responded to the call by opposition leader Viktor Yushchenko for them to reject government censorship.
A correspondent on the state channel, UT1, announced live on the evening bulletin that the entire news team was going to join the protests in Independence Square. She said their message to the protesters was: "We are not lying anymore".
For the first time in years, the UT1 bulletin aired opposition views in a balanced way after the station's management acceded to the journalists' demands.
It was the culmination of a rebellion among journalists at the state-run channel that had been brewing for days.
Even the sign-language presenter said that in an earlier bulletin, she had rejected the pro-government script and informed her viewers instead of the allegations of vote-rigging.
The news staff at UT1 were not alone. A couple of hours earlier, journalists on the pro-government private channel One Plus One took a similar stand.
The station had announced earlier in the day the resignation of its news editor, who had been presenting a fiercely pro-government election special for the past three days, after journalists refused to produce news bulletins in protest at censorship of the opposition.
In the reinstated evening bulletin that replaced the election special, the channel's director Oleksander Rodnyansky stood in front of a solemn group of his colleagues to deliver a brief statement.
He began by saying: "The One Plus One TV channel fully resumes its news and political and social broadcasting.
State TV has now started broadcasting opposition rallies
"We understand our responsibility for the biased news that the channel has so far been broadcasting under pressure and on orders from various political forces."
Mr Rodnyansky went on to say that the station would now guarantee "full and impartial" news coverage, allowing all viewpoints to be expressed. The subsequent bulletin lived up to this promise.
This new balance in TV coverage on previously government-controlled channels means that pictures making plain the huge size of the opposition demonstrations can now reach the heartland of Mr Yanukovych's support in the east of the country.
Rolling news coverage of the protests by Channel 5 - the one station fully backing the opposition - had earlier been blocked in the region.
The Ukrainian media played a big role in boosting Mr Yanukovych's election chances by denying the opposition any airtime to make its case and ridiculing his challenger, Mr Yushchenko. Reporters say the government issued lists of what they could and could not show.
Now that Ukrainian journalists have openly rebelled against such tight government control, Mr Yanukovych appears to have lost one of the key pillars of his support. It is another clear sign that the momentum behind the opposition is growing ever stronger.
BBC Monitoring, based in Caversham in southern England, selects and translates information from radio, television, press, news agencies and the internet from 150 countries in more than 70 languages.