With two days to polling, the Prime Minister said she was determined to ensure the police and security services had the powers they needed to deal with violent extremists plotting attacks on Britain.
Addressing supporters at a rally in Slough, she said they could include new measures to restrict the movements of suspects who have not been convicted of any offence as well as making it easier to deport foreign suspects.
Senior Conservative sources indicated they were ready to opt out of the relevant provisions of the European Convention on Human Rights (ECHR) if powers to stop suspects using mobile phones and computers or to impose curfews needed to be toughened up.
The move came as Mrs May faced intense pressure over her record on security in the wake of the London Bridge and Borough Market terror attack.
Liberal Democrat leader Tim Farron accused her of “simply posturing”, having been prepared to offer up the police for “cut after cut” when she was home secretary.
In her speech to supporters, Mrs May said she would change any laws that prevented the police and security services from dealing effectively with the extremist threat.
“As we see the threat changing, evolving, becoming a more complex threat, we need to make sure that our police and security and intelligence agencies have the powers they need,” she said.
“I mean longer prison sentences for people convicted of terrorist offences.
“I mean making it easier for the authorities to deport foreign terrorist suspects back to their own countries.
“And I mean doing more to restrict the freedom and the movements of terrorist suspects when we have enough evidence to know they are a threat, but not enough evidence to prosecute them in full in court.
“And if our human rights laws stop us from doing it, we will change the laws so we can do it.
“If I am elected as prime minister on Thursday, that work begins on Friday.”