Conservatives have launched a direct onslaught on Jeremy Corbyn's fitness to be prime minister, as polls suggest Labour is eating deep into Theresa May's lead as the June 8 General Election approaches.
The Tories released a video showing the Labour leader boasting about opposing anti-terror legislation and dodging questions over whether he would condemn the IRA.
And Home Secretary Amber Rudd suggested that victory for Mr Corbyn would "absolutely" increase the risk of future atrocities.
The attacks came as Mr Corbyn made his strongest attempt yet to distance himself from the IRA, saying he was "appalled" by the terror gang's 1991 mortar attack on Downing Street.
He said: "The bombing campaign was completely wrong because it was taking civilian lives."
And the Labour leader announced that he would recruit an additional 1,000 staff to the security and intelligence agencies MI5, MI6 and GCHQ to help in the battle against extremist violence.
Denouncing the Tories' traditional claim on the mantle of the "party of law and order", Mr Corbyn said Conservative-led governments had slashed numbers of police, border guards and emergency workers.
He said: "Ensuring the safety of our communities demands properly resourced action across many fronts.
"It means upholding and enforcing our individual rights, promoting community relations, supporting our emergency services, tackling and preventing crime and protecting us from danger, including threats of terror and violence."
Ms Rudd told the Mail on Sunday she spent much of her working life signing security warrants, while Mr Corbyn had spent his career opposing anti-terrorism measures.
"He talks now as though he could defend the country, but for 30 years he's been against (anti-terrorism measures)," she said.
"I spend two hours every day signing security warrants. The only thing Corbyn would sign is our security away. He'd be a disaster."
Asked if she was suggesting the prospect of Mr Corbyn in Downing Street meant an increased risk of atrocities, she stressed that she was not linking it to the Manchester bomb, but added: "It absolutely does, yes."
A clutch of General Election polls showed the Tory lead over Labour shrinking, with one new poll by ORB for the Sunday Telegraph putting Mrs May's party just six points clear, and another by YouGov for the Sunday Times recording the gap as seven points.
They followed a YouGov poll on Friday which suggested the comfortable Conservative lead of as much as 25 points at the time the snap election was called had narrowed to as little as five, putting at risk Mrs May's hopes of increasing her slender 17-seat majority.
The Sunday Times reported that "nervous" Tories were planning a relaunch of their campaign, focusing on the choice between Mrs May and Mr Corbyn to lead Britain's Brexit negotiations with the EU.
Meanwhile, Mrs May revealed details of a new Commission for Countering Extremism which she will set up if she wins the election, with a remit to help government identify policies to defeat extremism and promote "pluralistic" values.
She revealed the Commission will be charged with clamping down on "unacceptable cultural norms" such as female genital mutilation, as well as acting to ensure that women's rights are upheld in all of Britain's ethnic and religious communities.
Four polls in the Sunday newspapers gave Tories leads of between six and 12 points, but all but one suggested that Labour was making up ground, with one putting the party on 38% - matching its highest since Mr Corbyn became leader.
The surveys found support for Tories ranging between 43% and 46% and for Labour between 34% and 38%, with Liberal Democrats trailing on 7%-9%.
Liberal Democrat leader Tim Farron said: "No wonder Theresa May's court is at loggerheads. Theresa May is betraying pensioners and primary school children because she just doesn't care.
"If Theresa May wants to re-launch her campaign by talking about Brexit, my message to her is: bring it on.
"She is trying to force through an extreme Brexit that will damage the British economy and leave us isolated when we need to work with our friends to keep us safe. We will argue to give the people a say on the final deal."
Mr Corbyn said he has been vocal in opposing "executive control orders that are not subject to judicial oversight" as he defended his previous voting record on anti-terror measures.
Appearing on ITV's Peston On Sunday, Mr Corbyn said: "I do support work with the police and our security services on intelligence-led actions."