A dozen countries working on ways to end Venezuela's crisis on Thursday gave their backing to opposition leader Juan Guaido as parliamentary speaker, rejecting the

claims of a rival.

The International Contact Group on Venezuela said it was deeply concerned by events in the Venezuelan National Assembly this week in which the security forces of President Nicolas Maduro tried interfered in the vote to choose a speaker.

Guaido, whose claim to be acting president is recognised as legitimate by more than 50 countries, was re-elected speaker of the assembly on Sunday while rival lawmaker Luis Parra also claimed the title after a separate vote.

"We support Juan Guaido as President of the National Assembly, and reaffirm our commitment to actively support genuine efforts towards a peaceful and democratic resolution of the crisis in Venezuela," the statement said.

Guaido was re-elected by opposition lawmakers in a session held at a newspaper office after police blocked him from entering the National Assembly, while Parra proclaimed himself speaker after claiming to have been elected with 81 votes in the 167-member chamber.

"These events together with the continuous intimidation and reprisals against the members of the National Assembly, democratically elected by the Venezuelan people, further aggravate the crisis, creating more obstacles to the peaceful return to democracy and the rule of law," said the statement -- signed by all members of the group except Uruguay.

Guaido's re-election is important for his struggle against far-left leader Maduro, as the National Assembly is the only branch of government in opposition hands.

While Guaido enjoys international support including from Washington, Maduro appears entrenched with the crucial backing of the armed forces, despite presiding over the oil-rich country's collapse into economic ruin.

The EU has an arms embargo in force against Venezuela as well as individual sanctions on various members of the regime over human rights abuses.

The statement was signed by Bolivia, Britain, Costa Rica, Ecuador, France, Italy, Germany, the Netherlands, Panama, Portugal, Spain and Sweden -- a diplomatic vehicle set up to help mediate a political solution to the Venezuelan crisis.AFP