A leading international human rights group is calling the Turkish government's decision to block YouTube a "disastrous move" for freedom of expression and the right to access information.
Human Rights Watch urged Turkey to restore access to YouTube, as well as Twitter, which it banned last week.
The New York-based rights organization said the restrictions violate Turkey's obligations under international human rights law and domestic law.
Turkey blocked access to YouTube after audio was posted to the video-sharing website Thursday that appeared to be a leaked recording of Turkey's foreign minister and other top officials discussing possible military action in Syria.
The Turkish government blocked Twitter after the micro-blogging service was used to circulate other audio files implicating Turkish Prime Minister Recep Tayyip Erdogan and his son in corruption.
The ban was met with international condemnation, and a Turkish court on Wednesday ruled it illegal.
Erdogan described Thursday's audio leak as "villainous." He called the leaks an attempt to discredit him and his Justice and Development party ahead of key local elections set for Sunday.
Erdogan's Sunni-dominated government has supported elements of the Syrian opposition fighting to unseat the Iran-backed government of President Bashar al-Assad. Analysts say Turkey is also a key entry point for military supplies bound for rebels.
The United Nations refugee agency says more than 600,000 Syrian refugees are encamped inside Turkish territory. The Syrian uprising entered its fourth year earlier this month.