The Defence Secretary has warned Jeremy Corbyn would put Britain's security at risk if elected as prime minister.
Sir Michael Fallon denied being opportunistic as he attacked Mr Corbyn after the Labour leader reiterated his personal opposition to Britain's Trident nuclear deterrent.
A Labour spokesman said the party still supports Trident as its official position.
Sir Michael - who said Theresa May would fire Britain's nuclear weapons as a "first strike" if necessary - told ITV News the Labour leader had got his party into a "very dangerous muddle" that "would put the security of this country at risk".
He also attacked Mr Corbyn after Mrs May's rival said, as prime minister, he would order an immediate review of "all aspects" of defence and refused to say whether he would order drone strikes on terror leaders.
Sir Michael also rejected claims he was attempting to push a narrative by warning of a Labour-SNP coalition in the build-up to June 8's election.
Mr Corbyn last week ruled out any post-election coalition with the SNP after Nicola Sturgeon's party confirmed it would work with other parties to keep the Tories out of power.
The defence secretary, though, raised the prospect of the parties linking up in government.
"We're seeing the chaos now inside Labour and the chaos of a coalition if Labour got into power with the SNP," he told ITV News.
"We simply don't know which policies would remain and which would be jettisoned.
"That's why we need strong and stable leadership that Theresa May and the Conservatives are offering."