With Washington hinting it might soften its tough stance to break the deadlock, top US negotiator, Christopher Hill, said the two sides needed to review the situation.
He later left his job as a U.S negotiator to become a U.N negotiator 
( z1 leave :ARG0 ( z2 he ) :ARG1 ( z3 job :poss z2 ) :ARG2 ( z4 become :ARG1 z2 :ARG2 ( z5 person :ARG0-of ( z6 negotiate :ARG1 ( z7 country :name ( z8 name :op "U.S." ) ) ) :mod ( z9 organization :name ( z10 name :op "U.N." ) ) ) ) :time ( z11 after ) )