Twitter announced on Thursday that it has developed technology that it would allow it to selectively block tweets if a country wants it done.

“Until now, the only way we could take account of those countries’ limits was to remove content globally,” said a blog posting from Twitter. “Starting today, we give ourselves the ability to reactively withhold content from users in a specific country.”

In the posting, Twitter said that certain countries have a vastly different interpretation of what should be posted on the microblogging site. “Some differ so much from our ideas that we will not be able to exist there,” it said.

Twitter said the content blocked in one country, will still be available to the rest of the world. In the past, when the company deleted a tweet, it would disappear completely.

“If and when we are required to withhold a Tweet in a specific country, we will attempt to let the user know, and we will clearly mark when the content has been withheld,” the company stated.

Media watchdog Reporters Without Borders (RSF) has criticized the move in an open letter to Twitter executive chairman Jack Dorsey urging him not to cooperate with censors.

The letter says it amounts to “geolocated censorship” that would cooperate with local authorities in quashing free speech on the Internet.

The watchdog said content blocking restricts the freedom of expression at a time of great social upheaval in some parts of the world, citing the Arab Spring movements that spread across the Middle East and North Africa last year.

“By finally choosing to align itself with the censors, Twitter is depriving cyber dissidents in repressive countries of a crucial tool for information and organization,” reads a letter from RSF.

RSF says that Twitter’s new policy is too vague and will be abused by people in positions of power. “As is the case in China, will just a phone call from a government official or a local police station suffice to justify denying access to content?” the letter asks.