A key ally of Jeremy Corbyn has attacked the US for imposing sanctions on Venezuela, as pressure grows on the Labour leader to condemn President Nicolas Maduro.

Mr Corbyn has gone on holiday without commenting on events in Caracas, where the President has grabbed nearly unlimited powers and apparently detained opposition leaders.

Two years ago, the Labour leader hailed the improvements in housing, health and education under Venezuela’s Socialist leaders as a “cause for celebration”.

In 2014, Mr Corbyn rang to congratulate President Maduro live on a Venezuelan television channel, where Maduro introduced him as a “friend of Venezuela”.

Now Chris Williamson, a Labour shadow home office minister and key Corbyn supporter, has turned on Washington for its response to the Venezuelan crisis.

He told BBC's Newsnight he was not an “apologist” for the country’s Government, adding: “Clearly they've made mistakes, they didn't do enough to diversify the economy.”

But he said the US had “aided and abetted” violent protests in Venezuela, part of its “very shady record, going back many decades, of interfering in Latin America”.

Mr Williamson said: “They're under incredible pressure and there's a very one-sided, one-eyed view of the situation there very often in the British media.

“I'm yet to hear any criticism of the right-wing opposition or indeed the United States' intervention there and the sanctions.

“And clearly it can't be right, can it, that in a situation where there is a massive crisis in Venezuela at the moment to impose sanctions on the country.

“Surely it'd be far better, wouldn't it, to try and bring the sides together to facilitate talks and to encourage the right-wing opposition to stop these protests on the streets.”

Some Labour MPs have joined Conservatives in calling on Mr Corbyn to speak out, after evidence of vote-rigging in the poll to create a new assembly to grant Maduro sweeping new powers.

The European Union has condemned “the excessive and disproportionate use of force by security forces” and cast doubt on whether the election could be recognised.

One of the companies behind the voting system election said it believed results were inflated by at least 1m votes - a claim strongly rejected by Maduro.

Widespread protests against the government have been going on since April, as food and medicine prices soar because of plunging oil prices, with more than 121 people killed in the unrest.

One Labour MP, Angela Smith, said: “I think Corbyn needs to condemn the actions of the Venezuelan regime, which are a very serious threat to democracy in that country.”

A second, Graham Jones, agreed the country was “pretty close to being a dictatorship”, adding: “Jeremy, at some point, will have to make a statement.”

Mr Corbyn, a keen cyclist, is on a cycling holiday in Croatia, taking a break from plans to visit around 40 target seats in a summer of campaigning.

Emily Thornberry, Labour’s Shadow Foreign Secretary, has, through a spokesman, criticised Maduro’s “increasingly authoritarian rule”

The spokesman said Labour had already called for the Venezuelan government to respect human rights and the rule of law and warned against “further repression and violence”.

The comments echoed a statement issued, earlier this week, by her deputy, Liz McInnes, which said Labour was urging all sides to end the bloodshed.