Istanbul (dpa) - International activist groups Tuesday condemned the arrests of three people in Turkey, including a leading figure in a key Turkish human rights organization, over their support of a pro-Kurdish newspaper.The three activists were arrested on Monday over their support for an embattled newspaper that targets a Kurdish audience and have been accused of helping to spread "terrorist" propaganda, according to the Dogan news agency.The non-governmental organization Reporters Without Borders said it was "stunned to learn that an Istanbul court today ordered the pre-trial detention of its Turkey representative, Erol Onderoglu, and two other journalists on a terrorism charge."Both Amnesty International and Human Rights Watch demanded the immediate release of the activists and a halt to the investigation.Amnesty International called the arrests "legally baseless," adding that the present case was "one of countless investigations under Turkey‘s anti-terror laws targeting dissenting voices in civil society."German politicians Tuesday joined in the criticism of Turkey‘s vague anti-terror laws, which are already at the centre of a spat between Ankara and the European Union. The EU has demanded that Turkey narrow its laws before granting Turks visa-free access to the bloc.Three of the arrested activists had acted as symbolic editors of the pro-Kurdish newspaper Ozgur Gundem, which has been under pressure from the government over alleged ties to the banned Kurdistan Workers‘ Party (PKK).Turkey and Kurdish militants restarted armed conflict last year, after a ceasefire and peace talks collapsed.Meanwhile, the UN Correspondents Association said that journalist Razi Canikligil of the English-language daily newspaper Hurriyet, who had been arrested in Istanbul on Monday, was released on Tuesday.Canikligil was arrested based on articles he wrote regarding Turkish authorities, the correspondents association said earlier.Conditions for journalists in Turkey have worsened over the past year, activists say. The country is ranked 151 out of 180 countries on the Press Freedom Index compiled by Reporters Without Borders.