Jeremy Corbyn has condemned Tory manifesto proposals on social care, claiming Theresa May's "nasty party has launched a shameful attack on older people".
Shadow chancellor John McDonnell has also claimed the Conservative manifesto threatens the living standards of pensioners and working people.
On Twitter, Mr Corbyn said: "If you're a pensioner @Theresa_May is taking your vote for granted. She'll take away your winter fuel payment. Labour won't."
And in a second tweet, he said: "If you're a pensioner, @Theresa_May takes you for granted. She'll make you pay for visits from care workers if you own a home. Labour won't."
But defending the social care proposals in her manifesto, the Prime Minister said her plans will ensure elderly people receive the dignified and high quality care they deserve.
"Those elderly people who've been worried about how they pay for care in their home won't have to worry about that in the future," she said.
"They won't have to pay while they're still alive, they won't have to sell their home while they're living in it.
"What we also see is those people who are worried that their savings - have done the right thing and saved through their life and worried their savings will dwindle to nothing - we're quadrupling the threshold at which assets will be protected to £100,000."
But Mr Corbyn responded: "Theresa May's nasty party has launched a shameful attack on older people - introducing a compassion tax to force those in need of social care to pay for it with their family home. Labour is standing up for pensioners and guaranteeing the triple-lock on state pensions, as well as giving social care the funding it needs."
Labour claims the Tory manifesto places three new burdens on older people:
:: Scrapping the 'triple lock' on state pensions
:: Means testing Winter Fuel Payments - hitting 10 million pensioners
:: Forcing those who need social care to pay for it using their home
Labour's shadow business secretary Rebecca Long-Bailey accused the Conservatives of mounting an "all-out attack" on the living standards of pensioners.
She told a news conference in London: "They have laid bare the threat they pose to pensioner security and living standards and shown beyond a doubt that they are turning their backs on older people and future generations of pensioners.
"Those people who worked hard, they did everything that was asked of them, they put their blood, sweat and tears into making Britain great. Today they must feel like they have been kicked in the teeth."
While Labour accuses the Tories of threatening pensioners' living standards, the Conservatives are making a pitch to Labour voters in Scotland as they launch their Scottish manifesto.
The Prime Minister campaigned in Scotland only a few weeks ago and now the Tories' Scottish leader Ruth Davidson will claim that with the "help" of Labour voters, her party can defeat the Scottish National Party in "many places" across Scotland.
The SNP leader, Nicola Sturgeon, was one of five party leaders taking part in a TV debate on Thursday that was snubbed by the Prime Minister and Mr Corbyn.
And yet, bizarrely, while the debate was going on, the Labour leader posted another tweet, saying: "Theresa May, why not debate me?
"The public deserve to see a debate between the only two people who could form the next government."
But Conservative Party chairman Sir Patrick McLoughlin said after the debate: "Tonight gave a glimpse of the chaos you could get in just three weeks with all the other parties propping up Jeremy Corbyn as Prime Minister.
"Getting Brexit right is central to everything - and it's clear this coalition of chaos just want to return to division, and would undermine our Brexit negotiation and Britain's long-term economic security. It's too big a risk and we'd all pay the price with higher taxes, more debt and fewer jobs."
:: And don't forget to watch it on Sky News: The Battle For Number 10 on Bank Holiday Monday 29 May at 8.30pm.