The Turkish parliament has approved a bill that would tighten government controls over the internet.
The new law will allow Turkey's telecommunications authority to block websites without first seeking a court ruling.
It will also force internet providers to store data on web users' activities for two years and make it available to the authorities.
The opposition has criticised the move as an assault on freedom of expression.
Internet access in Turkey is already restricted and thousands of websites blocked.
Turkish Prime Minister Recep Tayyip Erdogan has been openly critical of the internet, calling Twitter a "scourge" and condemning social media as "the worst menace to society".
Both Twitter and Facebook were widely used by anti-government protesters to spread information during demonstrations last year.
The new measures were adopted after hours of debate in parliament where Mr Erdogan's governing Justice and Development Party (AKP) dominates with 319 of the 550 seats.
At the start of the debate, opposition MP Hasan Oren compared Mr Erdogan to Adolf Hitler.
"When you came to power you talked of enhancing democracy in Turkey - now you are trying to implement fascism," he said.
"Remember that Adolf Hitler used the same methods when he rose to power."
However, Deputy Prime Minister Bulent Arinc said there was "no such thing as internet censorship" in Turkey.
"We are freer compared to many other countries and have freedom of the press," he said.
The Organisation for Security and Co-operation in Europe (OSCE) said the new powers meant Turkey's telecommunications agency would be able to "gather communications data about all internet users without any legal limits or restrictions" and with users "never... able to know when and how this information is gathered".