The chairman of Amnesty International Turkey has been detained in the western city of Izmir along with 22 other lawyers over alleged links to the Gulen movement, an organisation that the government blames for last year's coup attempt, according to Turkish authorities and the UK-based rights group.

Amnesty International condemned the move by Turkish authorities after Taner Kilic's arrest on Tuesday for having suspected ties with the Gulen group. The group added his home and office were searched by the police.

State media said Kilic was detained for using ByLock, an encrypted communication software which the government says is used by members of the outlawed group.

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"The fact that Turkey's post-coup purge has now dragged the chair of Amnesty International Turkey into its web is further proof of just how far it has gone and just how arbitrary it has become," Salil Shetty, Amnesty International's secretary-general, said.

"In the absence of credible and admissible evidence of their involvement in internationally recognised crimes, we are calling on the Turkish authorities to immediately release Taner Kilic along with the other 22 lawyers, and drop all charges against them."

Turkey accuses Fethullah Gulen, a religious leader who lives in self-imposed exile in the US, and his group of orchestrating the coup attempt last summer which killed around 300 people and led to arrests in the country.

The government said the purges and detentions are aimed at removing Gulen supporters from state institutions and other parts of society.

Local and international rights groups, as well as many of Turkey's European allies, say the arrests and purges are arbitrary, claiming that the government is using the coup attempt as a pretext to silence opposition in the country.

'Judiciary should be prudent'

Orhan Miroglu, a member of the parliament's human rights commission, said the investigation into the Gulen group is wide-reaching due to the size and 40 year-history of the organisation.

"It's unfortunate that the head of a reputed human rights organisation has been detained," Miroglu, who is also an MP with the ruling Justice and Development Party, told Al Jazeera.

"However, people are investigated over Gulen links regardless of their affiliation. The judiciary allows all suspects to defend themselves and investigations are carried out according to the rule of law. Nonetheless, the judiciary should act prudently to avert possible suffering of innocent parties," he added.

READ MORE: Turkey suspends 9,000 police officers for 'Gulen links'

"People who are detained or sacked are released or get back to their jobs in state institutions after they are cleared. This is valid for people who allegedly used ByLock or have been investigated for other possible links to the terrorist group."

According to Amnesty International, Kilic has served on the board of Amnesty International Turkey for various periods since 2002 and has been the group's chairperson since 2014. 

During his work for human rights organisations in Turkey, he has consistently demonstrated an unswerving commitment to human rights, Amnesty said.

Follow Umut Uras on Twitter: @Um_Uras

Source: Al Jazeera News