Facebook network hit by 'sophisticated' attack
"This attack was not the work of amateurs, and we do not believe it was an isolated incident," Twitter information security director Bob Lord said in a blog post at the time.
Lord said there was an "uptick in large-scale security attacks aimed at US technology and media companies," as he told of Twitter detecting attempts this week to get unauthorised access to data in the firm's network.
The attack coincided with the revelation of several high-profile security breaches. The New York Times and The Wall Street Journal said that they had been hacked, and pointed to attackers from China.
It was unknown whether the cyberattack on San Francisco-based Twitter was related to high-powered hacker assaults on Facebook, the Times or the Journal.
Brazen cyberattacks on America's most high-profile media outlets revived concerns over Chinese hackers, who analysts say are likely linked to the secretive Beijing government.
The Times and the Journal reported that their computer networks had been compromised, alleging it was an effort by the Chinese government to spy on news media operating in the country.
The administration of President Barack Obama is trying to counter the electronic theft of trade secrets by lodging formal protests, expelling diplomatic personnel, imposing travel and visa restrictions, and complaining to the World Trade Organization, the Post said.