UK Home Secretary Amber Rudd said Facebook’s WhatsApp messaging platform should open its encryption to security services to help prevent terrorist attacks, Bloomberg reported.

Rudd said a recent attack on the UK’s Parliament building in which a total of five people died and around 50 were injured, means it is now important the country’s intelligence services are granted access to services like WhatsApp.

According to media reports, the attacker had used WhatsApp in the run up to the incident.

Rudd said the internet is “serving as a conduit, inciting and inspiring violence, and spreading extremist ideology.”

In an article in The Telegraph, she wrote: “We need the help of social media companies, the Googles, the Twitters, the Facebooks of this world. And the smaller ones, too: platforms such as Telegram, WordPress and Justpaste.it. We need them to take a more proactive and leading role in tackling the terrorist abuse of their platforms.”

Telegram is also an enrypted messaging app.

A WhatsApp company representative said: “We are horrified by the attack carried out in London…and are cooperating with law enforcement as they continue their investigations.”

Getting access to WhatApp messages for criminal investigations has long been a bone of contention. In Brazil, a judge sought to block WhatsApp for not handing over information in a case.

WhatsApp claims it doesn’t have the data the government wanted. When it added end-to-end encryption to all its messages last year, it said: “When you send an end-to-end encrypted message, no one else can read it – not even us”.

In January, the company refuted claims governments could decrypt message streams via a backdoor, and vowed to fight any attempts to force it to open access.

The FBI has managed to unlock iPhones in order to obtain data, but messaging tools are harder to get access to, the Bloomberg report said.

WhatsApp backed Apple in its row with the FBI over unlocking an iPhone in relation to a shooting.