The attempted crackdown came after links to wiretapped recordings suggesting corruption were posted on Twitter, causing Prime Minister Recep Tayyip Erdogan's government major embarrassment before local elections on March 30.
The government's effort to shut down the service backfired on Friday, with many 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 approved." Turkey's move to block Twitter sparked a wave of international criticism.
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 couldn't immediately be verified.
Government officials said Friday they were engaged in talks with Twitter and would restore access as soon as an agreement with the company is reached. Twitter said it hoped the dispute would be resolved soon. The government accuses Twitter of refusing to remove offensive content despite Turkish court orders.
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. The communications minister, Lutfi Elvan, would not confirm, saying he had not been informed about such a move. The Google system was accessible again Saturday afternoon.
Swedish Foreign Minister Carl Bildt used Twitter on Saturday to tell Turkey its efforts to block access to the social media network were "stupid." He said the blockade "isn't working and also backfiring heavily."
A statement from the Turkish government's Public Diplomacy office said the network was engaged in "systematic character assassinations" for hosting accounts where the leaked the wiretapped recordings have been posted. It said the audio tapes were "illegally acquired" or "fake and fabricated."
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 Jan. 1, he said without elaborating.
The government blocked access to Twitter after Erdogan threatened to "rip out the roots" of the website over the 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 graft probe.
Erdogan says that recording is fabricated and insists he is a victim of a plot orchestrated by followers of a U.S.-based Muslim cleric who want to discredit the government before the elections.