The North had refused to comply with the February agreement to shut down its only nuclear reactor until it received the $25 million, which the United States had linked to money laundering and counterfeiting.
The North Korean Foreign Ministry said today the money was finally returned, after a complex bank transfer via Russia, and that Pyongyang would begin to implement the disarmament deal.
"The funds frozen at the above-said bank were finally wired as demanded by the DPRK side, thus settling the controversial issue of the frozen funds," North Korea's KCNA news agency quoted a Foreign Ministry spokesman as saying.
"Now that the issue of de-freezing the funds has been settled, the DPRK, too, will start implementing the February 13 agreement on the principle of action for action."
The statement came one day before inspectors from the United Nations' International Atomic Energy Agency were due to arrive in Pyongyang.
It's the first time UN inspectors have returned to North Korea since being kicked out almost five years ago.
The four-member team, headed by Olli Heinonen, the IAEA's deputy director in charge of global nuclear safeguards, is expected to stay for five days in North Korea.
North Korea will from June 26 hold "a discussion on the suspension of the operations of nuclear facilities, its verification and monitoring" with IAEA inspectors, the Foreign Ministry spokesman said.
The closing of Yongbyon in exchange for fuel oil is the first step of the February deal.
The eventual goal is for the North to completely scrap its nuclear program in exchange for aid, security guarantees, and better diplomatic standing.
The agreement was reached in talks involving China, Japan, Russia, the two Koreas, and the United States.
(compiled from agency reports)