Turkey's government has accused Twitter of allowing defamation a day after social media users evaded a government attempt to block access to the network.
The government said that Twitter had refused to remove offensive content despite Turkish court orders.
A statement from the Turkish government's public diplomacy office on Saturday said the network was engaged in "systematic character assassinations" for hosting accounts where leaked wiretapped recordings were posted.
The office said the audio tapes were "illegally acquired" or "fake and fabricated". The recordings suggesting corruption have caused Prime Minister Tayyip Erdogan's government major embarrassment ahead of Turkey's March 30 election.
Lutfi Elvan, the communications minister, said: "Whether it's Twitter, Yahoo or Google, all social media companies have to obey the laws of the Turkish Republic and they will."
Turkey had made 643 content removal requests to Twitter since January 1, he said.
Government officials said they were engaged in talks with Twitter and would restore access as soon as an agreement with the company was reached.
Twitter said it hoped the dispute would be resolved soon.
Turkey's state-run news agency, Anadolu, said Twitter had begun on Saturday to close down accounts which the Turkish government has been complaining about, but the report could not immediately be verified.
On Saturday, Hurriyet newspaper and Twitter users said the clampdown was expanded to Google's Domain Name System, which had provided many of Twitter's Turkish users an alternative means of gaining entry.
Elvan would not confirm this, saying he had not been informed about such a move. The Google system was accessible again on Saturday afternoon.
Erdogan earlier this week threatened to "root out" the platform over links to recordings that appear to incriminate him and other top officials in corruption. In one recording a man believed to be Erdogan is heard instructing his son to get rid of vast amounts of cash from a home amid a police corruption probe.
However, Erdogan said the recording was fabricated and insisted he was a victim of a plot orchestrated by followers of a US-based Islamic leader who wanted to discredit the government before the election.
The government's effort to shut down the service backfired on Friday, with many Twitter users finding ways to continue to tweet and mock the government for what they said was a futile attempt at censorship.
Even President Abdullah Gul worked around the ban, tweeting that shutting down social media networks cannot "be
The move was criticised globally, with the vice-president of the European Commission, Neelie Kroes, tweeting that the ban was "groundless, pointless, cowardly".
Carl Bildt, the Swedish foreign minister, used Twitter to tell Turkey its efforts to block access to the social media network were "stupid". He said the shutdown "isn't working and also backfiring heavily".
Source: Associated Press