Berlin - Two more German citizens have been arrested in Turkey "for political reasons", Berlin said on Friday, as Chancellor Angela Merkel warned Ankara that Germany could re-examine its policies following the latest Turkish action.The latest arrests bring the total number of German political prisoners in Turkish custody to 12 at a time when ties between the two countries have badly frayed.There is "no legal basis" for detention in most of these cases, Merkel said, according to remarks carried by Germany's DPA news agency."And that's why we need to react decisively here," she said, adding that the government would "perhaps have to rethink" its policies vis-a-vis Turkey.Foreign ministry spokesperson Maria Adebahr said earlier on Friday that "on August 31, two German nationals were detained in Turkey for political reasons".The German consulate in the western city of Izmir was first informed of the arrests. Confirmation of the arrests then came not from the Turkish government but from Antalya airport police, Adebahr said.She declined to give further details about the case, saying only that German authorities had not yet been allowed access to the two."Our demands to Turkey are very clear," said Chancellor Angela Merkel's spokesperson Steffen Seibert. "We expect Turkey to release the German nationals who were arrested on unjustifiable grounds."Of the 55 Germans currently detained in Turkey, 12 of them - including four with dual German-Turkish citizenship - are being held for political reasons, the foreign ministry said.Troubled relationsRelations between the two NATO allies have deteriorated sharply after Berlin sharply criticised Ankara over the crackdown that followed last year's failed coup attempt.The arrest of several German nationals, including the Turkish-German journalist Deniz Yucel, the Istanbul correspondent of the Die Welt daily, further frayed ties.Yucel has now spent 200 days in Turkish custody ahead of a trial on terror charges.German journalist Mesale Tolu has been held on similar charges since May, while human rights activist Peter Steudtner was arrested in a July raid.Following Steudtner's arrest, Germany vowed stinging measures impacting tourism and investment in Turkey and a full "overhaul" of their troubled relations. Turkish President Recep Tayyip Erdogan, for his part, has also sparked outrage after charging that Germany is sheltering plotters of last year's coup, as well as Kurdish militants and terrorists, and demanded their extradition.Erdogan added to the tensions this month when he urged ethnic Turks in Germany to vote against Merkel's conservatives and their coalition partners, the Social Democrats, in September 24 elections.On Friday, Merkel hit out against Erdogan's call, saying Germany's election "will be decided only by the people in our country, who have German citizenship".The escalating tensions have split the Turkish community in Europe's top economy, the largest diaspora abroad, which is a legacy of Germany's "guest worker" programme of the 1960s and 70s.