"Some people say that it is not for government to regulate when it comes to technology and the internet. We disagree."

That defiant statement was included in the platform of Prime Minister Theresa May's Conservative Party ahead of Thursday's general election. In the wake of a terror attack that killed at least seven people in London, the pledge has taken on added significance.

May has long been a stalwart for tighter control and surveillance of internet communications, citing public safety concerns.

On Sunday, as Britain assessed the damage caused by three terror attacks in just three months, May reiterated her pledge to combat terrorism by denying extremists digital tools used to communicate and plan attacks.

"We need to work with allied democratic governments to reach international agreements that regulate cyberspace to prevent the spread of extremist and terrorism planning," she said in a speech. "We need to do everything we can at home to reduce the risks of extremism online."

The prime minister said internet companies provide extremist ideology "the safe space it needs to breed." Google (GOOGL), Apple (AAPL), Facebook (FB), Microsoft (MSFT) and many other services have created encrypted channels that may shield communications from law enforcement.

May already scored one major, hard-fought victory against internet companies in November 2016, with the passage of a law that she championed called The Investigatory Powers Bill.

Dubbed the "Snooper's Charter," the law gives U.K. law enforcement broad powers to hack into phones and look through web browsing records. It can force internet service providers to store data for 12 months, and gives legal backing to bulk collection of internet traffic data.

It's not exactly clear what additional powers May is now seeking.

Related: Theresa May says Internet must be regulated to prevent terrorism

In the past, May and her party have pushed for backdoor access to encrypted messaging apps that would require internet companies to allow governments to snoop on otherwise private communications.

Her government called for such a backdoor after it emerged the killer in March's terror attack near the Houses of Parliament used WhatsApp just minutes before stabbing a police officer to death. On Sunday, Home Secretary Amber Rudd called for limits on the "amount of end-to-end encryption that terrorists can use."

End-to-end encryption means that only the sender and the recipient can ever see messages sent via apps with the feature. It is impossible for third parties -- including tech companies -- to peek into users' conversations.

The United States has called for similar backdoors. Former FBI director James Comey lobbied Congress last year to pass a law that would require internet companies to let U.S. law enforcement spy on encrypted communications. Comey's proposal gained traction after the FBI had difficulty getting into the iPhone used by the shooter in an attack in California.

Other countries have taken more extreme measures to combat encryption technologies. For example, Brazil has repeatedly banned WhatsApp. China effectively bans internet companies from providing encryption services. India has proposed requiring internet companies share private communications with law enforcement.

Related: London terror attack was 8 minutes of terror and mayhem

In late 2015, during his campaign for president, Donald Trump called for "closing that Internet up in some way" in "certain areas." It was unclear what he meant, and as president, Trump has not proposed any such measure.

Internet companies have lobbied hard against governments' efforts to disrupt encrypted communications.

In pushing back against the FBI's calls for backdoor channels, Apple cited privacy concerns. Technically, any backdoor that could be used by the government could also be exploited by hackers, foreign governments or bad actors looking to steal or do harm, Apple claimed.

Facebook has doubled down on privacy in WhatsApp even after governments have fought hard against it, recently making the app encrypted from end-to-end. Microsoft, Google, Twitter and many other internet companies have also voiced their strong support for powerful encryption tools.

Open Rights Group, which advocates for privacy and free speech online, said that May's approach is "very risky."

"If successful, Theresa May could push these vile networks into even darker corners of the web, where they will be even harder to observe," the group said in a statement.