BRUSSELS (AP) — European Union leaders have been unable to agree on setting up a back-channel with Moscow to ensure that the bloc’s interests are protected should progress be made in negotiations to end Russia’s war on Ukraine , some of them said on Friday. European Council President António Costa, who chaired their two-day summit, had directed his office to reach out to the Kremlin and proposed a senior official to make contact. Costa said his aim was not to mediate or set up a parallel