Priti Patel says it is "right and proper" that MPs are accessible to members of the public following Sir David Amess' killing - and stressed that politicians' safety and an open democracy "can absolutely be balanced".
The home secretary's comments came as a spokesperson for the National Police Chiefs' Council (NPCC) confirmed every parliamentarian will be contacted about their security arrangements today by a chief constable as part of a review into MPs' safety.
Operation Bridger, a nationwide police protective security operation established in 2016, will reach out to the more than 600 MPs to discuss their security arrangements following the murder of Sir David at a constituency surgery on Friday - with officers then reporting their findings back to Ms Patel.
The NPCC spokesperson also encouraged MPs to "immediately report any security concerns" to their local forces and said funding for additional security measures is available through the Independent Parliamentary Standards Authority (IPSA) based on threat assessments made by police.
On Friday, Ms Patel confirmed she had asked all police forces to immediately review security arrangements for MPs after the killing of Sir David in Leigh-on-Sea, Essex.
It is understood the home secretary would like to see security for MPs across the country become more standardised and uniform as currently there is a variation in the level of security various members decide to take out.
At present, most backbench MPs will not have the police protection offered to senior ministers.
Sir David died after being stabbed at a surgery - where MPs offer face-to-face meetings with constituents - in his Southend West constituency.
Speaking to reporters from the scene on Saturday morning, Ms Patel confirmed a review into MPs' safety is under way "to make sure that they are protected so that they can go around serving their constituents in an open way, but in a safe way".
The home secretary said "further guidance" led by Commons Speaker Sir Lindsay Hoyle will shortly be given to MPs.
"We cannot be cowed by any individual or any motivation - people with motives who stop us from functioning to serve our elected democracy - so on that basis we have measures in place," Ms Patel said.
"We will continue to review and strengthen the measures and rightly so.
"The Speaker and I will continue to support MPs, policing will continue to support MPs - that work is under way.
"And we will continue to absolutely stand by the principles that we are elected by to serve our constituents in the open way in which we have been doing so, but also recognising that there are safety and protection measures that we have to undertake to."
The review is being conducted as part of Operation Bridger - a nationwide police protective security operation to enhance the security of members of parliament that began after the murder of Labour MP Jo Cox in 2016.
Following the launch of the operation five years ago, many MPs were given fobs that connect them to emergency services and panic alarms that they could place in their homes and offices.
On Friday, Sir Lindsay promised to "examine" safety measures for MPs following the killing of Sir David, but cautioned against a "kneejerk reaction".
"Nothing will stop democracy, nothing will stop us carrying out our duties," he told Sky News
Ms Patel's comments came as a senior Conservative MP called for a temporary pause in face-to-face meetings between parliamentarians and their constituents following the killing of Sir David.
Tobias Ellwood, who was hailed as a hero for his attempts to save the life of PC Keith Palmer during the Westminster terror attack in 2017, said physical engagements should be halted until the Home Office has completed its review of MPs' security.
Posting on social media on Saturday morning, Mr Ellwood, who chairs the influential Commons Defence Select Committee, said: "MP engagement with the public: This is a vital part of our work - our accessibility with the public.
"But understandable huge anxiety amongst MPs now. Until the home secretary's review of MP security is complete I would recommend a temporary pause in face to face meetings."
However, not all MPs are of the view that normal business should be temporarily disrupted in the wake of Sir David's killing.
Conservative former minister David Davis told Sky News he disagrees with fellow Tory Mr Ellwood's suggestion that face-to-face meetings between MPs and constituents should be paused, adding: "I don't think it would be a good reflection of David's memory to stop that in any way."
Mr Davis told Sky News: "Whilst we all love him and admire him, what we shouldn't do in response to his tragic murder is break that link which he was the absolute champion of."
He continued: "I mean, sure we should be cautious - maybe we should do things to try to ensure that people who come to see us are bona fide and so on - but I think actually pausing it would be a bad idea.
"It would be a terrible reflection of what David (Amess) stood for. David himself was the ultimate constituency MP and you can see that in the response from people in his constituency."
Conservative MP for High Peak, Robert Largan, said he would be continuing with his weekly advice surgery on Saturday and invited members of the public to come along without an appointment.
Another Conservative MP John Redwood posted on social media: "We must ensure our representative traditions continue as David Amess would wish.
"Violence must not stifle open debate nor the safe access of MPs to constituents' views. Margaret Thatcher spoke the morning after the Brighton bomb to make the point murderers do not win."
Meanwhile, Kim Leadbeater, the sister of Jo Cox, who is now a Labour MP herself, said that many MPs will be "scared" by the death of Sir David.
"My partner came home and said 'I don't want you to do it anymore, because the next time that phone goes it could be a different conversation'," she said.
Fellow Conservative MP Steve Brine was asked by Sky News if he has had fears for his own safety while an MP.
"Oh yeah, You bet," he replied.
And Labour minister Lucy Powell said Greater Manchester Police have ensured "extra support" is in place for her following the killing.
She tweeted: "I've had a number of reassuring calls from Greater Manchester Police today. Some extra measures and support being put in place. Much appreciated."
Veteran Labour MP Harriet Harman said she will be writing to the prime minister asking him to back a Speaker's Conference to review the safety of parliamentarians in their constituencies following the death of Sir David.
The amount of money spent protecting MPs rose substantially following the murder of Ms Cox in June 2016.
Accounts from the Independent Parliamentary Standards Authority showed MPs spent £2.5m on security in 2016/17 - up from £170,000 the previous year.
The murder of Ms Cox came six years after Stephen Timms was stabbed twice in the stomach at a constituency surgery in east London.
In January 2000, Andrew Pennington died while saving the life of Cheltenham MP Nigel Jones when they were attacked with a Samurai sword.