Britain's interior minister says the country has entered a new phase of global terrorism.

Home Secretary Amber Rudd told the House of Commons on Thursday that 13 plots linked to or inspired by Islamist extremists were foiled between June 2013 and the Westminster Bridge attack in March this year. She says five plots have been prevented since March.

Rudd says that "we now believe we're experiencing a new trend in the threat we face."

Rudd says more must be done to tackle the extremists who want to "radicalize and weaponized" young people in Britain.

Security services have been warning for months that U.K. nationals who have traveled to fight with the Islamic State group pose a danger to Britain when they return home.