North Korea begins to reassemble its main nuclear facility

North Korea has begun to reassemble its main nuclear facility, citing a delayed removal from a U.S. list of terror sponsors, Japanese media reported Wednesday.

Japan's public broadcaster NHK and Kyodo News agency said North Korea started putting its Yongbyon facility back together Tuesday, days after it halted disablement work. The reports cited unidentified officials related to the disarmament talks.

North Korea last week said it had stopped disabling its nuclear reactor and threatened to restore the plutonium-producing facility, citing Washington's failure to remove it from the list of terror sponsors.

In response, Washington repeated its demand that North Korea must first agree to a plan to verify an accounting of nuclear programs it submitted in June, if it wants to be taken off the list.

Kyodo said the reassembling started at the Yongbyon facility on Tuesday.

Fox News carried a similar report from Washington, quoting an unidentified U.S. official as saying that the North has been threatening the move for some time and it is considered as a way for it to express anger and "to put further pressure on us."

Fox News also said the official said the reassembling is seen as a "symbolic gesture" because the facility has been largely taken apart.

South Korean and U.S. officials have said that it would take at least a year for the North to restart the facilities after they are completely disabled.

Japan's Foreign Ministry officials said the report could not be confirmed immediately.

The South Korean Foreign Ministry said in a statement Wednesday that it was trying to verify the contents of the Fox News report.

The ministry said it was concerned that the North's possible launch of work to restore the nuclear facilities in Yongbyon could cause "serious damage" to disarmament efforts. It urged North Korea to resume work to disable the complex.

North Korea began disabling its nuclear plant in Yongbyon, north of Pyongyang, in November, but the communist country slowed the work to protest a delay in the provision of promised aid from its negotiating partners.

Disarmament efforts reported major progress in June after the North submitted its long-delayed nuclear declaration and destroyed its nuclear cooling tower in a show of its commitment to denuclearization.

The U.S. then announced it would delist the North from the terrorism blacklist, a coveted goal of the North's cash-strapped communist regime.