A plane carrying 35 Russian diplomats and their families, who have been expelled by order of President Barack Obama, has arrived back in Moscow.

The 35 were told to leave Washington last week in response to an alleged hacking scandal.

Republican Senator John McCain has called for an even tougher stand against Moscow.

“We will be working for much tougher sanctions against Russia. They attacked the United States of America. The hacking was an attack and we should treat it as such. We think their financial institutions and other aspects of the Russian economy should be addressed.”

But at a New Year celebration President-elect Donald Trump repeated his scepticism over US intelligence gathering and the wisdom of blaming the Russians.

“Well, I just want them to be sure, because it’s a pretty serious charge, and I want them to be sure. And if you look at the weapons of mass destruction, that was a disaster, and they were wrong. And so I want them to be sure. I think it’s unfair if they don’t know.”

The Russian diplomats were given just 72 hours to pack up and leave. President Obama is convinced Moscow hacked the Democratic Party and Hillary Clinton’s presidential campaign last year.

Russian President Vladimir Putin had been expected to engage in ‘tit-for-tat’ expulsions but instead he said he would not “stoop” to irresponsible diplomacy. He also said he would review US relations once Trump takes over.

Donald Trump praised the decision calling it “very smart”.