Information belonging to about 250,000 users may have been viewed.
The hackers attempted to gain access to Twitter's user data earlier this week, the social media giant said on a blog post Friday.
Twitter said it has contacted affected users via email and has reset the pilfered passwords following the cyber attack.
The online social networking service has more than 200 million active users and is among a growing list of victims of Internet security attacks.
The Washington Post disclosed in an article on their website that the newspaper was the target of a sophisticated cyber attack in 2011.
The company's spokeswoman, Kris Coratti, didn't offer any details regarding the attack but did say security is their No. 1 priority.
"Like other companies in the news recently, we face cyber security threats," Coratti was quoted as saying. "We have a number of security measures in place to guard against cyber attacks on an ongoing basis."
Other American newspapers including The New York Times and The Wall Street Journal also reported this week that their computer systems had been infiltrated by China-based hackers.
Officials believe the hack is part of an aggressive cyber-spying campaign by the Chinese government aimed at monitoring media coverage and stealing classified information and corporate secrets to intimidate critics.
The Chinese government has defended itself among similar accusations in the past.
"Chinese law forbids hacking and any other actions that damage Internet security," the Chinese Defense Ministry recently said. "The Chinese military has never supported any hacking activities."
Twitter's director of information security, Bob Lord, said that the attack "was not the work of amateurs, and we do not believe it was an isolated incident."
"The attackers were extremely sophisticated, and we believe other companies and organizations have also been recently similarly attacked," Lord said. "For that reason we felt that it was important to publicize this attack while we still gather information, and we are helping government and federal law enforcement in their effort to find and prosecute these attackers to make the Internet safer for all users."
Although Twitter does not believe the hacking yielded any important secrets, they fear stolen passwords could be used to eavesdrop on private messages.
Ashkan Soltani, an independent privacy and security researcher, said few people bother using different passwords for different services.
"More realistically, someone could use that as an entry point into another service," Soltani said.
The Associated Press contributed to this report.