President Maduro of Venezuela and the country’s electoral authorities have rejected accusations of fraud in last Sunday’s vote for a new constituent assembly.

The company behind the voting system has said it was tampered with to inflate the turnout – and that the real figures were at least a million below the government’s estimate of over eight million.

Before a televised gathering of supporters, Nicolas Maduro turned on what he called “a firm with its headquarters in London and bank accounts in the US”.

“The stupid president of Smartmatic pressurised by the gringos and the British said there were over seven million voters. I believe there were more than 10 million Venezuelans who came out onto the streets and more than 8 (million) voted. The rest had to face the barricades,” Maduro said.

Turnout is seen as a key indicator of government support.

The president insisted that the election was transparent and properly audited. Maduro also criticised a report by Reuters. The news agency claimed it had seen election documents which showed that fewer than four million votes had been cast two hours before polls closed – in turn casting doubt on the official outcome.

Venezuela’s Attorney General Luisa Ortega Díaz, who had already called the new Constituent Assembly illegitimate, told CNN she had launched an investigation into the vote.

The new assembly will have the power to sack the chief prosecutor and dissolve the opposition-run Congress.

Last month the Congress swore in more than 30 judges in defiance of the pro-government Supreme Court, which promptly declared the appointments unconstitutional.

At least three judges have been detained, while another three have taken refuge in the Chilean ambassador’s residence in Caracas.

International condemnation has been widespread, with Maduro accused of a power-grab and presiding over economic chaos; the president says the new assembly is needed to bring peace and stability.