Twitter blocked two accounts on Sunday that had been used to spread corruption allegations against Turkish Prime Minister Recep Tayyip Erdogan, his government and his inner circle.
The move came after high-level meetings between the government and executives from the company last week, and after the Turkish government provoked a storm in March by trying to ban the network entirely.
The two accounts blocked on Sunday - @Haramzadeler333 and @Bascalan -- leaked large amounts of secret documents and recorded phone conversations implicating Erdogan, his family and associates in a wide-ranging corruption scandal.
Between them, @Haramzadeler333 (which translates as "Sons of Thieves") and @Bascalan (which means "Prime Thief", a play on the Turkish for prime minister) had close to one million followers on Twitter.
Users reported that the two accounts were listed as "withheld" when they tried to access them from within the country over the weekend.
Twitter's global policy team said it withholds content only "after due process", such as after having received a court order, and in a tweet said it would not do so "at the mere request of a gov't official".
It added that it would not give details of the two accounts' users to the government.
"Twitter has not provided and will not provide user information to Turkish authorities without valid legal process," it said.
The government, which accuses those behind the accounts of publishing false and harmful content, is also pressing the US-based company to hand over details on the owners of a dozen other accounts.
@Haramzadeler333 and @Bascalan appeared to have privileged access to information and documents related to a 15-month police investigation into the corruption allegations.
Erdogan has accused a "parallel state" controlled by US-based Muslim cleric Fethullah Gulen of orchestrating the graft scandal against him, using a widespread network of allies in the police and judiciary.
The embattled premier has asked Twitter - which has 10 million users in Turkey - to open a liaison office in the country. He has also criticised the company for not paying taxes there.
Twitter has ruled out any such move, refusing to open an office in a state that tried to ban it, and has rejected charges of tax evasion. It said its advertising sales in Turkey are handled through a reseller that pays applicable taxes.
Erdogan's government had to unblock Twitter on April 3 after the country's top court ruled that the ban breached constitutional guarantees on free speech.
The video-sharing site YouTube has been blocked in Turkey since the end of March despite two separate court orders calling on the ban to be lifted, after an audio recording allegedly made during high-level security talks on Syria was posted on the site.