Telesur claims to be totally different from its rivals

The new channel's director, Aram Aharonian, told the BBC it would be the first large-scale broadcasting project to challenge regional power structures.

He said Latin Americans wanted to see each other through their own eyes.

The network plans to show its first programmes in July, before going on air 24 hours a day in September.

The new channel, backed by left-wing governments in Argentina, Uruguay and Cuba, will show news, documentaries and Latin American films.

It hopes that Brazil will join the project at a later stage, though the country is working on its own network project.

'Not a weapon'

The test transmissions began with a summary of the new channel's objectives, a documentary on its inception and trailers for other programmes.

Critics of the new network say it will be a propaganda mouthpiece for Venezuela's left-wing president, Hugo Chavez.

But Telesur's president Andres Izarra, who is also Venezuela's information minister, denied any ideological agenda.

"This will be a window through which we will be able to know and view ourselves... but it's not a weapon to promote political models and views," he said.

Mr Aharonian said the network would be "totally different" from rivals CNN and Spain's TVE.