North Korea has offered to return to multilateral talks on its nuclear programme if the US releases assets frozen in a bank in Macau.
Kim Kye Gwan said N Korea was bolstering its military
"The minute we have the funds... I will be at the talks," a spokesman said.
Washington froze the funds it claims are linked to illegal activities by North Korea, including money laundering and the counterfeiting of US dollars.
Six-nation talks on North Korea's nuclear programme began in 2003 but have been stalled since last year.
North Korea has refused to rejoin the negotiations until the US lifts the financial sanctions, under which about $24m (£14m) of funds have been frozen.
Washington denies the sanctions are related to the nuclear deadlock, saying they are a separate issue.
The North's top nuclear negotiator Kim Kye-gwan made the latest comments as he was leaving Tokyo, where efforts to revive the stalled talks ended without a breakthrough.
In September last year North Korea agreed to dismantle its nuclear programme in return for aid and security guarantees.
However, attempts to find a formula to implement the deal have made no headway.
Mr Kim said that while the talks were deadlocked, North Korea was taking the opportunity to bolster its military deterrent forces.