From the given sentence, extract the phrase (often noun or verb) that carries the given relationship. The generated phrase should be present in the sentence.

Given Relationship: 'be president of', Sentence: 'Barack Obama today becomes the first black president of the United States of America .'
president

Given Relationship: 'attack', Sentence: 'Egypt and Syria attacked an unsuspecting Israel , making significant advances before being pushed back by the Israelis .'
attacked

Given Relationship: 'declare war on', Sentence: 'When the United States declared war on Spain , American Red Cross President Clara Barton , at age 76 , traveled to hospitals recruiting nurses to work for the Army at medical camps in Florida and Cuba .'
declared