A senior State Department official says the U.S. is consulting with South Korea, China, Russia and Japan over ways for the U.S. to hold follow-up talks with North Korea.

U.S. Acting Assistant Secretary of State for Public Affairs Michael Hammer made the remark on Monday during a news briefing for foreign correspondents in New York.

He said the U.S. is “involved with its six-party partners to try to see if there is any opportunity for those talks to resume.”

Hammer stressed that the North needs to “abide by its commitments and responsibilities dating back to the 2005 joint statement and it must take credible steps toward denuclearization.”

Meanwhile, State Department spokesman Mark Toner said the U.S. has yet to assess whether the North is sincere about denuclearization and improving ties with the South.

He said the he doesn’t think the U.S. has enough examples or evidence to make a decision in either direction.