The use of military force is still an option to end the political crisis in Venezuela if President Nicolás Maduro continues killing protesters, the opposition leader Juan Guaidó says.

The president of the National Assembly told the BBC's James Menendez that another option would be a military transition as long as it lead to free elections.

Mr Guaidó, who led a failed attempt to spark a military uprising against Mr Maduro in April, said there was still momentum for change in the country.

He has been recognised as interim leader by more than 50 nations, including the US and most in Latin America but Mr Maduro retains the loyalty of most of the military and important allies such as China and Russia.