"We are going to try to set the agenda and figure out how we can most efficiently use these two days here in Geneva," Hill, US assistant secretary of state for East Asian and Pacific Affairs, told journalists before leaving for the talks.
Asked whether he was optimistic or pessimistic regarding the talks, Hill replied: "I am neither. I am just doing my job."
On Friday, Hill had said the US delegation was "hopeful" the two sides could draw up an implementation arrangement for the disablement and declaration of North Korea's nuclear facilities.
North Korea has already shut down a key nuclear reactor at Yongbyon under an agreement reached on February 13.
Under the deal, North Korea agreed to dismantle its nuclear programme in return for aid and security and diplomatic guarantees, notably normalising ties with the US.