FILE - In this Feb. 26, 2016 file photo, Palestinian activist Issa Amro, center, participates in a demonstration in the West Bank city of Hebron. Leading rights groups called Tuesday, Aug. 5, 2017, for the release of Amro who was detained by Palestinian security forces after criticizing the autonomy government of Palestinian President Mahmoud Abbas in the Israeli-occupied West Bank. Amro is the founder of the group Youth Against Settlements in volatile Hebron, where Jewish settlers live in heavily guarded enclaves in the center of the city. (AP Photo/Mahmoud Illean, File)

RAMALLAH, Palestinian Territory - A prominent Palestinian activist began a hunger strike Tuesday to protest his detention by the Palestinian authorities after he criticized the autonomy government of President Mahmoud Abbas.

Issa Amro was detained Monday by Palestinian security forces in Hebron, the West Bank's largest city, after he criticized the detention of a local journalist who had called for Abbas' resignation. Amro expressed his views in a Facebook post.

Leading human rights groups blasted Amro's detention. London-based Amnesty International and the Palestinian Independent Commission for Human Rights said it signals a growing crackdown on free expression in the autonomous Palestinian enclaves in the Israeli-occupied West Bank.

Amro is the founder of the group Youth Against Settlements in volatile Hebron, where Jewish settlers live in heavily guarded enclaves in the centre of the city.

Amro was on hunger strike to protest what he said was an unlawful detention, made without a warrant or due process, said his brother, Ahmad Amro.

"Issa started a hunger strike today protesting his arbitrary arrest," he said. "He has been in detention for more than 24 hours without being presented before a prosecutor and without official charges."

Amro's lawyer, Farid al-Atrash, said he visited Amro and the detained local journalist on Monday.

"It is shameful for the Palestinian Authority to arrest such a strong activist against settlement activities and (Israeli) aggressions in Hebron," the lawyer said.

Amro, 35, also faces charges in an Israeli military court, including allegedly calling for illegal protests and obstructing the official duties of soldiers. Amro has said Israel is trying to silence him and Amnesty has called for the "baseless" charges to be dropped. His trial is to resume in October.

Al-Atrash said that Israel is trying to halt what he called Amro's "relentless struggle against settlement activities in Hebron."

Several hundred Israeli settlers live in heavily guarded enclaves in the midst of tens of thousands of Palestinians. Constant friction between the two populations makes the city a frequent flashpoint of violence.

Adnan Damiri, a spokesman for the Palestinian security forces, said he was not aware of the details of Amro's detention and declined further comment.

In July, Abbas clamped down on social media and news websites — the main outlets for debate and dissent in the West Bank — with a vaguely worded decree that critics say allows his government to jail anyone on charges of harming "national unity" or the "social fabric."

Rights activists have said the edict, issued without prior public debate, is perhaps the most significant step yet by Abbas' government to restrict freedom of expression in the areas it administers.

"It is outrageous that a prominent human rights defender has been arrested simply for voicing his opinion online," said Magdalena Mughrabi, deputy director for the Middle East and North Africa at Amnesty International.

"Criticizing the authorities should not be a criminal offence," she said in a statement. "Issa Amro's arrest is the latest evidence that the Palestinian authorities are determined to continue with their repressive campaign against free speech."

News from © The Associated Press, 2017