brussels u.s. secretary state rex tillerson tuesday say unite state remain commit europe offer public statement support european ally worry foreign policy president donald trump partnership america european union ... base upon share value share objectives security prosperity side atlantic remain commit tillerson say lunch 28 eu foreign minister tillerson brief statements eu foreign policy chief federica mogherini two take question say visit show strong commitment u.s. european alliance important role european alliance play share security objectives brussels tillerson offer eu strong u.s. support