Brussels - Top European Union officials are to hold talks with Turkey's foreign minister against a backdrop of growing concern that Ankara is sliding away from EU values as President Recep Tayyip Erdogan tightens his grip on power and cracks down on perceived opponents. Tuesday's talks come with Turkey's long-standing bid for EU membership in the deep freeze and criticism of Erdogan's authoritarian rule swelling, particularly in powerful EU member state Germany. Those strained relations will likely cast a shadow over discussions between EU foreign affairs chief Federica Mogherini and Turkey's Foreign Minister Mevlut Cavusoglu and EU affairs ministers Omer Celik in Brussels. Discussions are expected to touch on issues including Ankara's EU accession, immigration, Turkey's demands for visa-free travel for its citizens, the fight against terrorism and energy and trade ties.