“This week, we detected unusual access patterns that led to us identifying unauthorized access attempts to Twitter user data. We discovered one live attack and were able to shut it down in process moments later,” according to Twitter director of information security, Bob Lord.
Twitter believes that the people behind the recent account hackings were not amateurs, and that Twitter was not their only target. Some recent major hacking of websites includes the New York Times and the Wall Street Journal, both of which are considered to be the work of Chinese hackers’. Some believe the slew of hacked websites may have something to with recent criticisms of Chinese Prime Minister Wen Jiabao by the media. (Source)