Prominent human rights activist Issa Amro will be detained for at least a further 24 hours after he criticised, on Facebook, the arrest of a journalist.
The Palestinian prosecutor on Wednesday extended his detention, wih the Palestinian Authority claiming he had stoked "sectarian tensions" online.
Amro, who lives in the West Bank city of Hebron, is the latest victim of a growing crackdown being waged by Mahmoud Abbas against journalists and critics on social media, activists and rights groups say.
He has denied the claims against him and has now begun a hunger strike to demand his release.
Amro came to prominence as the founder of Youth Against the Settlements, a group that has long documented alleged human rights abuses perpetrated by the Israeli army and settlers in Hebron.
His work has led him to face charges against him from Israeli military court.
Earlier this week, Ahmed Amro, the brother of the detained activist, told Middle East Eye that Israeli forces had come to their family home in Hebron on Sunday looking for Issa.
"“He went to them on Monday morning, and until now we haven’t heard from him. We have no way of communicating with him,” Ahmed Amro told MEE.
“My brother didn’t do anything wrong. We don’t know why they arrested him.”
Escalation in 'crackdown' against dissent
Responding to Amro's arrest, Sarah Leah Whitson, the Middle East Director at Human Rights Watch, condemned the Palestinian Authority for its arrest of Amro.
"The Palestinian Authority's detention of prominent coordinator of Youth Against Settlement Issa Amro, apparently for a Facebook calling on the PA to respect free speech, makes plain how little respect it has," said Whitson.
"Amro, who also faces charges in an Israeli military court for his role in a protest, and other Palestinian rights defenders are suffocating, stuck between an authoritarian local authority and a repressive occupation."
Amro is highly regarded in Palestinian society for his work in documenting Israeli human rights violations. His arrest had caught Palestinian politicians by surprise.
Some politicians had attempted to free him on Monday from the PA prison, according to the Guardian.
Amnesty International also condemned Amro's arrest and noted an “escalation” of the PA’s crackdown on dissent.
The PA began its crackdown in June when 29 websites, the majority linked to Hamas and Abbas's former Fatah rival Mohammed Dahlan, were banned.
An "electronic crimes' law was also introduced in July, setting out harsh penalties for a series of vaguely worded offences on social medial. this led to the arrest of a number of journalists.