The chief US negotiator to the talks has hinted that Washington could remove North Korea from the list of state sponsors of terrorism before it completely gives up its nuclear arms programme.
But the US has not said it has decided to strike Pyongyang from the list, which currently also includes Cuba, Iran, Sudan and Syria.
Speaking in the Swiss city of Geneva, Christopher Hill, the chief US negotiator, said on Sunday that North Korea had agreed to fully account for and disable its nuclear programme by the end of the year.
He did not say what, if anything, the US had offered in return for the latest pledge.
Pyongyang was put on the US list based on the confession of a North Korean agent over the mid-air explosion of a South Korean passenger jet over the sea off Myanmar in 1987.
The designation imposes a ban on arms-related sales, keeps the economically isolated country from receiving US aid and requires the US to oppose loans by the World Bank and other international financial institutions.
The North's spokesman said the Geneva talks had "laid the groundwork for making progress at the plenary session of the six-party talks" aimed at ending Pyongyang's nuclear ambitions.
North Korea has already shut down its nuclear reactor at Yongbyon under a six-nation agreement reached on February 13.
The talks also involve the US, China, South Korea, Japan and Russia.