WASHINGTON (AFP) - United States Secretary of State John Kerry on Friday condemned Venezuela's "unacceptable" use of force against anti-government protesters, and declined to respond to a call from Caracas for bilateral talks.

"The government's use of force and judicial intimidation against citizens and political figures, who are exercising a legitimate right to protest, is unacceptable and will only increase the likelihood of violence," Mr Kerry said in a statement.

Despite calls from Venezuela's democratic opposition and the international community, the government of Mr Nicolas Maduro "has confronted peaceful protesters with force and in some cases with armed vigilantes claiming to support the government," the top US diplomat added.

"It has imprisoned students and a key opposition figure. It has limited the freedoms of expression and assembly necessary for legitimate political debate."

He pointed to Mr Maduro's moves to tighten media restrictions, after CNN said several of its journalists working in Venezuela, on both Spanish-language and English-language programs, had seen their press credentials revoked or refused.

In a move filled with anti-US sentiment, Mr Maduro has threatened to block the American broadcaster, accusing the network of inciting "civil war." "This is not how democracies behave," Mr Kerry said.

The US secretary of state urged the Venezuelan government to release jailed dissidents "and initiate a process of genuine dialogue with the democratic opposition.

"The solution to Venezuela's problems can only be found through dialogue with all Venezuelans, engaging in a free exchange of opinions in a climate of mutual respect," said Mr Kerry, who also called on the opposition to refrain from violence.

The top US diplomat had nothing to say about Mr Maduro's challenge to US President Barack Obama for direct talks on the Venezuelan crisis.

Mr Maduro has accused Washington of fomenting the anti-government unrest. US officials have denied the charges.