Telegram will share user information with law enforcement when users are suspected of illegal activities.

• Telegram will share phone numbers and IP addresses of users involved in illegal activities with law enforcement
• Telegram’s search feature will now block users from finding or sharing illegal content

The messaging app Telegram has said it will hand over users' IP addresses and phone numbers to authorities who have search warrants or other valid legal requests.

The change to its terms of service and privacy policy "should discourage criminals", CEO Pavel Durov said in a Telegram post on Monday.

The announcement marks a significant reversal for Mr Durov, the platform’s Russian-born Co-Founder who was detained by French authorities last month at an airport just north of Paris.

Critics say Telegram has become a hotbed of misinformation, child pornography, and terror-related content partly because of a feature that allows groups to have up to 200,000 members.

Meta-owned WhatsApp, by contrast, limits the size of groups to 1,000.

Telegram was scrutinised last month for hosting far-right channels that contributed to violence in English cities.

Earlier this week, Ukraine banned the app on state-issued devices in a bid to minimise threats posed by Russia.

The arrest of the 39-year old chief executive has sparked debate about the future of free-speech protections on the internet.

After Mr Durov's detention, many people began to question whether Telegram was actually a safe place for political dissidents, according to John Scott-Railton, senior researcher at the University of Toronto's Citizen Lab.

He says this latest policy change is already being greeted with even more alarm in many communities.

"Telegram’s marketing as a platform that would resist government demands attracted people that wanted to feel safe sharing their political views in places like Russia, Belarus, and the Middle East," Mr Scott-Railton said.

"Many are now scrutinizing Telegram's announcement with a basic question in mind: does this mean the platform will start cooperating with authorities in repressive regimes?"

Telegram has not given much clarity on how the company will handle the demands from leaders of such regimes in the future, he added.

Cybersecurity experts say that while Telegram has removed some groups in the past, it has a far weaker system of moderating extremist and illegal content than competing social media companies and messenger apps.

Before the recent policy expansion, Telegram would only supply information on terror suspects.

Mr Durov said the app was now using “a dedicated team of moderators" who were leveraging artificial intelligence to conceal problematic content in search results.

But making that type of material harder to find likely won’t be enough to fulfill requirements under French or European law, according to Daphne Keller at Stanford University’s Center for Internet and Society.

“Anything that Telegram employees look at and can recognize with reasonable certainty is illegal, they should be removing entirely,It sounds like a commitment that is likely less than what law enforcement wants” Ms Keller said.

In some countries, they also need to notify authorities about particular kinds of seriously illegal contents.In Telegrams quarterly transparency reports, It is said that they will disclose whether it has provided user information to authorities.This change is part of a broader effort by the company to address concerns about illegal content and moderation on its platform.