The Labour leader “sounded like President Trump” in calling for dialogue with Vladimir Putin when the Russian double agent and his daughter had been left in “mortal danger” by the nerve-agent attack, he warned.
“What Jeremy Corbyn was saying was strangely like the kind of things that President Trump says about the need to engage in dialogue, to keep on talking to them,” the former Labour Foreign Secretary said.
“No-one is saying that all contact is going to be cut off – the question is whether or not there are actions as well as words. Because the truth is that it is only actions that shows the Russians we are serious.”
Asked if Mr Corbyn should have been “stronger”, Mr Miliband added: “I think it is about standing up for our own citizens, frankly, because it’s British citizens.
“Two of them are in mortal danger now. Apparently, 500 of them could have been affected by this nerve gas.”
The criticism comes after Mr Corbyn came under fire for raising huge donations to the Tory Party by wealthy Russian expats – moments after Theresa May’s statement blamed the Kremlin for the attack in Salisbury.
The Labour leader faced shouts of “shame” and “disgrace” when he said: “We’re all familiar with the way huge fortunes, often acquired in the most dubious circumstances in Russia, sometimes connected with criminal elements, have ended up sheltering in London and trying to buy political influence in British party politics.
“Meddling in elections, as the prime minister put it, and there has been over £800,000 worth of donations to the Conservative Party from Russian oligarchs and their associates.”
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And he added: “We need to continue seeking a robust dialogue with Russia on all the issues dividing our countries, both domestic and international, rather than simply cutting off contact and simply letting tensions and divisions get worse, and potentially even more dangerous.”
Some Labour MPs joined Conservatives in criticising Mr Corbyn, one saying he “did not understand the gravity of the threat which Russia poses to this nation”.
Speaking to BBC Radio 4’s Today programme, Mr Miliband praised the Prime Minister’s tone, in her Commons statement, giving Russia until midnight tonight to explain the nerve agent attack.
But he warned that tough action would be difficult without international support, pointing to Mr Trump’s reluctance to take on President Putin as a major obstacle.
“The biggest thing she has to do in the next two days is to rally her allies,” he said of Ms May’s task.
“It is very significant and very worrying, frankly, that the White House has not felt able to point the finger at Russia in the last seven or eight days.
“And, I think that rallying the European allies, and, if possible, significant strands of American opinion, is absolutely key.”
Dominic Raab, the housing minister, said possible retaliation included measures targeted at individual human rights violators.
A “whole panoply of counter-measures” including economic, financial and diplomatic, was being considered.