Twitter said Thursday that it now has the ability to block tweets from appearing in a specific country if legally required to do so.

"As we continue to grow internationally, we will enter countries that have different ideas about the contours of freedom of expression," Twitter said in a blog post.

"Some differ so much from our ideas that we will not be able to exist there," the San Francisco-based company said.

"Others are similar but, for historical or cultural reasons, restrict certain types of content, such as France or Germany, which ban pro-Nazi content," Twitter said.

Twitter said that previously, if it was required to remove messages, it could only remove them globally.

"Starting today, we give ourselves the ability to reactively withhold content from users in a specific country -- while keeping it available in the rest of the world," Twitter said.

"We haven't yet used this ability, but 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," it said.

Twitter said it would post details of any incidents involving the removal of content to ChillingEffects.org, a public database of takedown requests.

"One of our core values as a company is to defend and respect each user's voice," Twitter said. "We try to keep content up wherever and whenever we can, and we will be transparent with users when we can't."

China, notably, blocks Twitter, a situation which Twitter co-founder Jack Dorsey described recently as "unfortunate and disappointing." (AFP)