Turkey's lawyers' association has asked a court to overturn the country's ban on Twitter.
Turkey blocked access to the social media network overnight, hours after prime minister Recep Tayyip Erdogan threatened to "rip out the roots" of the website.
Links to audio recordings and documents implicating Mr Erdogan and other top officials in corruption have been posted on Twitter ahead of crucial local elections on March 30th.
Turkey’s main opposition party also said it would seek a cancellation of the ban.
The Twitter shutdown, which Turks began to notice around midnight last night, occurred 10 days before the local elections and came after Mr Erdogan lashed out at the social media site in an election rally in Bursa, a western town, on Thursday, saying he did not care about international reactions if national security was at stake.
“Twitter, mwitter! We will wipe out roots of all,” Mr Erdogan declared in a campaign speech. “They say, ‘Sir, the international community can say this, can say that.’ I don’t care at all. Everyone will see how powerful the state of the Republic of Turkey is.”
Mr Erdogan had faced perhaps the biggest challenge in his 11 years in office when unidentified critics began using Twitter and YouTube to leak dozens of phone calls and documents that seemed to tie government officials and business circles close to the government to a graft inquiry that began in December.
One of the recordings purports to be of the prime minister himself telling his son to get rid of large sums of cash on the morning of December 17th , when the homes of three former ministers’ sons were raided. Mr Erdogan has repeatedly - and angrily - insisted that the recording was fake.
The prime minister’s office issued a statement before the ban was imposed, underlining what it said was Twitter’s lack of co-operation after four local courts ruled that certain content must be removed. “The presidency of telecommunication made necessary attempts in line with court rulings, however, Twitter officials have remained indifferent to these requests,” said the statement, posted on the semiofficial Anadolu News Agency.
Unless the website co-operated, the agency added, “Technically, there would be no other option than blocking access to Twitter in order to reduce damages of our citizens.”
Social media networks in Turkey have grown more popular since anti-government protests last summer, when traditional media organisations were silenced under intense government pressure and journalists critical of Mr Erdogan were either fired or forced to resign.
Jim Prosser, a Twitter spokesman, said the company was “looking into” the ban, adding, “That’s all we have for the moment.” In Twitter messages, the company urged people to use mobile connections to get back on Twitter.
“This is certainly politically motivated prior to the local elections and the worst kind of political censorship I have seen,” said Yaman Akdeniz, a professor of cyber law at Istanbul’s Bilgi University. “Absence of Twitter from Turkey will be a significant democratic deficit.”
The government adopted further internet restrictions in February, citing the need to protect privacy. Those restrictions, which were sharply criticised by human rights groups in Turkey and abroad, allowed for the swift closure of websites or removal of Internet content by a court order in a matter of hours.
New York Times
