Theresa May and Jeremy Corbyn are both vowing action to improve security on Britain’s streets.
Mrs May is highlighting Tory plans for a new commission to counter extremism and “stand up” to Islamists and others who threaten British values.
Mr Corbyn says Tory cuts have undermined security and is pledging to recruit an extra 10,000 police and more security staff if Labour wins power.
The Conservatives say the Labour leader’s sums “don’t add up”.
The two party leaders have been engaged in a war of words over the best way to respond to the terror threat, in the wake of the suicide attack in Manchester that left 22 dead.
Mrs May earlier announced that the terror threat had been reduced from “critical” to “severe” but she warned people to “remain vigilant”.
The Conservative general election manifesto includes plans for a Commission for Countering Extremism, which the party says will identify extremism, including the “non-violent” kind, and help communities stand up to it.
‘Enough is enough’
The party has not released full details of how it will work but has promised it will be a statutory body with “proper teeth and a clear remit”.
Mrs May said: “Our enjoyment of Britain’s diversity must not prevent us from confronting the menace of extremism, even if that is sometimes embarrassing or difficult to do.
“Extremism, especially Islamist extremism, strips some people of the freedoms they should enjoy, undermines the cohesion of our society, and can fuel violence. And it can be especially bad for women.
“There is clearly a role for government in tackling extremism where it involves behaviour that is or ought to be criminal.
But there is also a role for government to help people and build up organisations in society to promote and defend Britain’s pluralistic values, and stand up to the extremists who want to undermine our values and impose their twisted beliefs onto the rest of us.”
She added: “Enough is enough. We need to be stronger and more resolute in standing up to these people.”
Mr Corbyn, meanwhile, will repeat Labour’s pledge to reverse cuts to police and emergency services staff he says have been carried out by the Conservatives.
Labour say they would recruit an extra 10,000 police officers, 3,000 more firefighters, 3,000 more prison officers, 1,000 more security and intelligence agency staff and 500 more border guards if Labour wins the general election, he says.
He is also promising extra staff for the security and intelligence agencies – GCHQ, MI6 and MI5 – in order “to better ensure our collective safety”.
He added: “As well as full funding for our frontline and first response services, Labour will properly resource the partner agencies in other frontline public services, including schools and colleges, and local authorities.
“These agencies are charged with a duty to identify those individuals vulnerable to violent extremism but under the current government they have been held back and barely been able to provide their own core services.
“Only Labour is serious about properly resourcing our security and frontline services.”
The Conservatives hit back at Labour’s promises, with Home Secretary Amber Rudd saying: “Jeremy Corbyn can promise what he likes, but can’t deliver anything because his sums don’t add up and he isn’t up to the job of keeping Britain safe.”
In Autumn 2015, the then Chancellor, George Osborne, promised to spend £3.4bn extra on counter-terrorism – an increase of 30% – over the following five years.