Government requests for Twitter users' data rose by 20% in the second half of 2012, the social network said on Monday.
The requests came from 30 countries around the world, but the vast majority were from the US and were usually linked to criminal investigations.
Updated figures on what government and rights holders have been asking of the social network were revealed in the second of its transparency reports and posted on a new site, transparency.twitter.com.
Twitter complied with requests by the US government 69% of the time, according to the report. The US government was responsible for 815 of the 1,009 information requests in the second half of 2012, it found. Most requests were coming from the US because Twitter is based in San Francisco.
Twitter said that its transparency report hoped to "raise awareness about these invasive requests."
"We believe the open exchange of information can have a positive global impact," Jeremy Kessel, Twitter's legal policy manager, said in a blogpost celebrating what activists have dubbed Data Privacy Day.
"To that end, it is vital for us and other internet services to be transparent about government requests for user information and government requests to withhold content from the internet; these growing inquiries can have a serious chilling effect on free expression and real privacy implications."
"All of our actions are in the interest of an open and safe internet."
Twitter's response to the requests varied, with the social network granting by far the highest number of US government requests. Most other government requests were not complied with. Twitter said it did not comply with requests that fail to identify a user in cases when a user may have challenged the request after it notified them, or when a request was overly broad.
The report, Twitter's second for 2012, provided more detailed statistics on US government requests for information than the first. The majority 60% of US requests were comprised of subpoenas from authorities, while the rest were made up of court orders and search warrants, it said. Twitter said it notifies users of the requests except when prohibited from doing so by a court order, which happened in 20% of cases.
Twitter's transparency report also noted an increase in requests for content removal, up from six in the first half of 2012 to 48, and a decrease in copyright notices, from 3,378 to 3,268.
In November, Twitter announced a new policy for dealing with copyright infringement claims in tweets.
A statement from Google on Monday, setting out its approach to government requests for information, said it was pushing for updating laws such as the US Electronic Communications Privacy Act to protect online documents.
It said: "It's important for law enforcement agencies to pursue illegal activity and keep the public safe. We're a law-abiding company, and we don't want our services to be used in harmful ways. But it's just as important that laws protect you against overly broad requests for your personal information. "