Hackers have accessed thousands of high-profile Twitter accounts to tweet a message praising Turkey and condemning the Dutch as "Nazis" early Wednesday, in a cyberattack that appears to have been executed through a popular data-tracking service.

Twitter Counter, a Netherlands-based site for Twitter analytics, tweeted Wednesday that it was investigating a hack that occurred overnight.

"We've already taken measures to contain such abuse," the service tweeted. "Assuming this abuse is indeed done using our system, we've blocked all ability to post tweets and changed our Twitter app key."

Affected users tweeted messages written in Turkish and accompanied by a swastika symbol, along with the hashtags #NaziManya and #NaziHollanda. A video attached to the tweets shows clips of Turkish President Recep Tayyip Erdogan condemning "Nazi Germany, Nazi Netherlands."

"Do not force the patience of Turkey," Erdogan says in the clip, in a translation provided by Storyful.

Accounts affected by the hack had their banner photos changed to the Turkish flag.

Many high-profile accounts were affected, including Forbes, UNICEF USA, soccer star Javi Martinez and Amnesty International

Baseball Canada, Canada Soccer, Justin Bieber's account in Japan and the Terry Fox Foundation were among the more prominent Canadian targets.

The hack came ahead voters going to the polls in the Netherlands, after an election campaign that saw populist candidate Geert Wilders challenge incumbent Prime Minister Mark Rutte. Wilders has been a vocal opponent of Islam and immigration, and has vowed to shut his country's borders, ban the Qur'an and withdraw from the European Union.

Dutch polls close at 4 p.m. Eastern Time.

Rutte has been locked in an ongoing war of words with Turkish President Recep Tayyip Erdogan, who recently called the Dutch "Nazi remnants" for blocking two Turkish ministers from campaigning in the Netherlands.

Dutch officials recently denied airport landing rights to the Turkish foreign minister, who was slated to address crowds at a rally in Rotterdam Saturday. Also on Saturday, Dutch riot police blocked the Turkish family affairs minister from entering the Turkish consulate in Rotterdam.

Erdogan responded to the incidents by claiming that "Nazism is alive in the West."

"If you sacrifice Turkish-Dutch relations to the elections on Wednesday, then you will pay the price," Erdogan said on Sunday. "Those who unleash the dogs and their hatred will pay the price."

The tweets were deleted en masse early Wednesday.

Twitter Counter sought to assure its users that their passwords and credit card information were not breached in the hack.

Like many other social media-integrated services, Twitter Counter requires users to allow access to their Twitter accounts.

With files from The Associated Press