Twitter has implemented additional security after a wave of attacks on the profiles of influential media outlets.
The social media service now allows users to log in with a two-step approach, similar to online banking, where users must enter a code which is sent separately by text message for each log-in.
Experts had been calling for such additional security measures for some time.
The Twitter accounts of the BBC, Associated Press and Financial Times were recently hacked, with the hackers getting the passwords via phishing emails and then seizing the accounts.
The hacker group Syrian Electronic Army took responsibility for the attacks, saying the western media had been providing false information about the civil war in Syria.
The AP attack was especially serious because the hackers sent a bogus announcement of an explosion in the White House that injured President Barack Obama, which resulted in a downturn in the US financial market.
In February, hackers got into the Twitter accounts of Burger King and Jeep and announced their companies were being sold to competitors.
Hackers usually obtain passwords through prepared emails with apparently harmless links. Additional text message codes would then stop password thieves from being able to log into an account.
The online service said previously authorized Twitter apps will continue to work without problems. But Twitter also said the text message system would not work with all mobile operators.
Google is also implementing a two-step log-in procedure. Instead of a text message, there is the Authenticator app in which pre-programmed codes are shown directly on the mobile device.