Twitter says it has revoked access to block "a third-party app" apparently used to hack a number of accounts to broadcast pro-Turkish messages.
It's not clear how many accounts were taken over late Tuesday but the targets appear to have been entirely random.
Twitter Counter, an Amsterdam-based third party Twitter analytics company, told The Associated Press it had started an investigation into the matter.
Hackers have hijacked a slew of Twitter profiles amid the ongoing diplomatic feud between Turkey and two European nations, Germany and the Netherlands.
Media reports including from Gizmodo, Engadget and the Guardian say a slew of accounts as varied as UNICEF, Duke University, Amnesty International and Starbucks Argentina have had their accounts compromised by hackers who used them to broadcast pro-Turkish messages.
Neither Twitter nor Twitter Counter immediately provided a figure for the number of accounts affected. UNICEF, Duke, Amnesty, Starbucks and others did not immediately return messages seeking comment, although they and other high-profile accounts appear to have since returned to normal.
The Twitter hijackings are the latest in a campaign of online vandalism that has followed from days of escalating tensions between Turkey and its European partners over Turkish politicians' hopes to campaign there ahead of their country's constitutional referendum next month. The dispute has devolved into angry nationalist chest-thumping, a display mirrored online by the defacement of a large number of random Dutch websites.
On Monday alone several hundred websites were hit at a single Dutch internet hosting provider, Versio, according to an employee who posted a message to the company's help forum.
The hackers who've claimed responsibility for the campaign have so far not returned messages from the AP.
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