Turkey has jailed six human-rights activists, including Amnesty International's Turkey chief, for allegedly aiding terrorists.

Police arrested the six during a raid on a hotel on the island of Buyukada on July 5, during a digital security workshop. On Tuesday a court in Istanbul ordered them to remain behind bars until a trial.

In addition to Amnesty's director of operations in Turkey, Idil Eser, German and Swiss human-rights workers were among the detainees.

Turkish media reports said the six are accused of having been in contact with Kurdish and leftist militants and suspected members of the movement led by exiled Muslim cleric Fetullah Gulen - once President Recep Tayyip Erdogan's close ally, but now at the top of the Turkish government's most-wanted list.

"This is not a legitimate investigation. This is a politically motivated witch hunt that charts a frightening future for rights in Turkey," Amnesty secretary general Salil Shetty said Tuesday.

The United States also condemned the arrests.

"Prosecutions like these with little evidence or transparency undermine Turkey's rule of law and the country's obligation to respect individual rights," State Department spokeswoman Heather Nauert told reporters.

The U.S. urged Turkey to drop the charges, free the six prisoners, and lift provisions of the country's state of emergency that allow what the U.S. spokeswoman called the "indiscriminate prosecutions of individuals."

Turkey extended its post-coup state of emergency three more months this week, shortly after voters narrowly approved a referendum to amend the constitution and expand President Erdogan's powers.

U.S. President Donald Trump congratulated Erdogan on his referendum victory, but many European Union leaders fear the impending constitutional changes will further erode human rights and free speech in Turkey and muzzle the opposition.

More than 50,000 people have been arrested during a yearlong crackdown since last year's coup. In addition, 110,000 civil servants, members of the military and law-enforcement agencies were dismissed for either participating in the coup or actively sympathizing with the plotters.

土耳其关押了六名人权活动人士，包括国际特赦在土耳其的负责人，罪名是帮助恐怖分子。

警方7月5日对王子岛一家旅馆发动突袭，逮捕了这六个人，当时他们正在参加一个数字安全研讨会。伊斯坦布尔一家法院星期二裁决，这六人继续关押，等待开庭。

除了国际特赦在土耳其的负责人艾德尔·伊瑟外，被捕的还有德国和瑞士人权工作者。

土耳其媒体报道说，这六个人被控跟库尔德、左翼激进分子，以及流亡的穆斯林教士居伦领导的运动成员有联系。居伦一度曾是土耳其总统埃尔多安的亲密盟友，如今已是土耳其政府通缉名单的首犯。

国际特赦秘书长萨利尔·赛迪说，“这不是合法调查，而是有政治动机的猎巫行动，让土耳其人权前景堪忧。”

美国也对这次逮捕事件表示谴责。

国务院发言人诺尔特告诉记者说：“这样毫无证据和透明度的迫害，削弱了土耳其的法治和土耳其尊重个人权利的义务。”

美国敦促土耳其放弃指控，释放六名在押者，结束土耳其紧急状态的相关规定。国务院发言人说，这些规定让土耳其政府可以“不分青红皂白地对个人进行迫害”。

本周早些时候，土耳其将未遂政变后实施的紧急状态延长了三个月。此前不久，土耳其选民以微弱多数批准了一项全民公决，修改宪法，扩大总统埃尔多安的权力。

美国总统川普对埃尔多安的全民公决胜利表示祝贺，但是很多欧盟领导人担心，即将出现的宪法改动会进一步侵蚀土耳其的人权和言论自由，让反对派无法发声。

土耳其未遂政变以来历时一年的镇压行动中，有5万多人被捕，还有11万公务员、军人和执法人员被解除职务，有些是因为参与政变，有些是因为积极同情政变策划者。