Oren Dorell and Victor Kotsev

USA TODAY

SOFIA, Bulgaria — Twitter remained blocked in much of Turkey on Friday, days before an election and amid a massive corruption scandal in which incriminating leaks keep getting posted on social media.

The outage began Thursday night, hours after Turkish Prime Minister Recep Tayyip Erdogan gave a fiery speech to supporters in which he vowed to "eradicate Twitter" to uphold the privacy of citizens.

"I don't care what the international community says," Erdogan said at a campaign rally in the city of Bursa. "Everyone will witness the power of the Turkish republic."

Erdogan said he took action against the Twitter messaging system because anonymous Twitter accounts provide links to YouTube audio of conversations purportedly between him and his son on the shifting of cash to avoid police scrutiny. He says the audio is fake.

Elections on March 30 for local offices mark the start of a critical 15-month voting cycle leading into presidential and parliamentary elections. Erdogan has said he is not running for re-election after 11 years in office, but that can change.

Erdogan's attack on Twitter is making headlines, said Ilhan Tanir, Washington correspondent for the Turkish daily Today's Vatan.

"Everybody's talking about this," Tanir said.

Some of Erdogan's government ministers defended the ban, citing privacy issues. Other officials, including President Abdullah Gul, have criticized the restrictions.

"The wholesale shuttering of social media platforms cannot be approved," Gul said Friday on his Twitter account @cbabdullahgul, which has more than 4.4 million followers.

Gul, a founding member of Erdogan's ruling Justice and Development Party (AKP), is a potential rival of Erdogan in the presidential elections this summer. Although public disagreements between the two remain rare, analysts say any signs of emerging differences could have an effect on Turkish politics.

"Abdullah Gul is undoubtedly the next most important person in the AKP, and he actually scores higher marks than Erdogan does in public opinion polls," said William Hale, a professor emeritus of Turkish politics at the School of Oriental and African Studies in London.

According to reports in the Turkish media, Twitter has hired a prominent cyber-law expert to challenge the ban, while many users in Turkey used virtual private networks and international domain name servers to circumvent the ban.

More than half a million tweets from Turkey were posted in 10 hours Friday despite the ban, the Turkish national daily Hurriyet reported. That's not a significant decrease from daily averages before the ban.

Across Turkey, a group effort to defy the block emerged Thursday night and Friday. Protesters spray-painted the names of IP addresses on walls and election billboards, and journalists explained on TV how to set up virtual private networks.

"Every Turkish citizen has become some kind of Internet expert/amateur hacker after the ban," tweeted Ipek Yezdani, an Istanbul-based journalist.

The recordings Erdogan seeks to squash were made public in February, when anonymous Twitter accounts posted links to YouTube audio files, then notified reporters of their locations. Their original source is not known publicly.

According to transcripts, the audio files are recordings of five telephone calls between Erdogan and his son, Bilal, on Dec. 17, the day police raided the homes of several government ministers and their sons and seized millions of dollars in cash.

In the transcript, one man informs another of a corruption raid that day targeting 18 people and instructs him to "take everything you have in the house out."

Turkey has blocked access to YouTube, but this is the first ban on Twitter, which is hugely popular in the country and was instrumental in organizing flash protests against the government last year.

Many users trying to access the network early Friday saw a notice from Turkey's telecommunication authority, citing four court orders. Twitter spokesman Nu Wexler said the company was "looking into this now." He didn't say whether an outage had occurred.

Twitter's @policy account sent out messages telling Turkish users in both English and Turkish they could send out tweets by using short message service, or "SMS." It was unclear whether tweets sent this way would be viewable within the country.

The Turkish telecommunication authority issued a statement accusing Twitter of violating "personal rights and the confidentiality of private lives" and said access would be restored only when Twitter removes "illegal content."

Contributing: The Associated Press. Dorell reported from McLean, Va.; Kotzev from Sofia