The company revealed that only 19 percent of the requests were made with a search warrant, while 60 percent were with subpoenas and 11 percent relied on court orders.
Twitter said it requires police to obtain a search warrant to access the contents of users' tweets and direct messages. The company said police can use subpoenas, which generally do not require a judge's approval, to seek basic subscriber information, such as the email address and a log of IP addresses used to access the account.
The Hill reported last week that Google, Microsoft, Yahoo and Facebook all began demanding in late 2010 or early 2011 that police obtain a warrant to access private user content.
Those policies go beyond the Electronic Communications Privacy Act (ECPA), a 1986 law that only requires police to obtain a subpoena to read emails, instant messages and other forms of digital communication that have been opened or that are more than 180 days old.
Senate Judiciary Committee Chairman Patrick Leahy (D-Vt.) is pushing legislation that would update ECPA to clarify that police need a warrant to seize electronic messages, regardless of how old they are.
"After three decades, it is essential that Congress update ECPA to ensure that this critical law keeps pace with new technologies and the way Americans use and store email today," Leahy said in a statement on Monday. "Digital privacy is important to all Americans, regardless of party affiliation or ideology."