Two anonymous Twitter accounts used to release secretly recorded conversations implicating family and associates of Turkey's prime minister and senior government officials in a corruption scandal appeared on Sunday to have been blocked.
Twitter last week agreed to comply with a Turkish government request to close some accounts that officials said had breached national security or privacy regulations.
The two accounts - Haramzadeler and Bascalan - each had more than 400,000 followers, who now see only a red circle with a line through it and cannot access any tweeted material.
Twitter said in a tweet on its policy feed: "Reminder: Our Country Withheld Content Policy means we act after due process, e.g., a court order".
"We don't withhold content at the mere request of a gov't official and we may appeal a court order when it threatens freedom of expression," it tweeted.
San Francisco-based Twitter did not refer specifically to the two Turkish accounts in its tweets, which appeared late on Saturday after the two accounts had apparently been blocked earlier in the day.
It did, however, tweet that it "has not provided and will not provide user information to Turkish authorities without valid legal process".
The block on the accounts came after the Constitutional Court on Friday granted an application by Prime Minister Tayyip Erdogan, who said they breached his privacy.
The action follows months of effort by Erdogan to crack down on social media after recordings leaked on the two Twitter accounts became public on December 17 and threatened to embroil his government in a graft scandal.
Erdogan reacted by pledging to "root out" social media and applied to the Constitutional Court to place limits on their activities. Twitter and YouTube were blocked for two weeks in March ahead of nationwide municipal elections.
Erdogan sees plot in leaks
The Twitter block was lifted 16 days ago after the Court ruled that it breached freedom of expression, a decision Erdogan has since said was wrong and should be overturned. YouTube remains partially blocked in Turkey.
In an effort to resolve the situation, Twitter officials led by the company's head of global policy Colin Crowell last week met officials from the prime minister's office, the communications ministry and telecoms authorities.
Transport Minister Lutfi Elvan said in a statement after the meeting that both sides had agreed that Twitter would "blur out" what he called "malicious content" subject to court decisions.
Erdogan applied to the Constitutional Court on Friday to challenge what he said was a violation of his and his family's privacy by social media. He also complained about the failure of social media to comply with a court order for the removal of content that he said breached his rights.
Erdogan has consistently dismissed the leaked recordings as a fabrication and part of a plot against him.
His critics saw the ban as the latest in a series of authoritarian measures aimed at quashing the scandal which had grown into one of the biggest challenges of his 11-year rule.
His Islamist-rooted AK Party emerged far ahead of rival parties in March 30 municipal elections that were seen as a referendum on his rule.