Iran is interested in improving ties with North Korea but that the Asian nation's debt to Tehran stands in the way of closer relations, Iran's foreign minister was quoted as saying Friday.

It was the first time an official of either country referred to their dealings, which are not publicly known. The extent of North Korea's debt remains unknown and officials have not provided any figures.

"It is necessary to remove some obstacles so that grounds for further cooperation between the two countries can be established," the official IRNA news agency quoted Iranian Foreign Minister Manouchehr Mottaki as saying.

The comments came after Mottaki's meeting late Thursday with visiting North Korean acting Foreign Minister, Kim Yong Il.

Pyongyang's "debts to Tehran is among the obstacles in the way of cooperation," Mottaki said without elaborating. "The two countries can find a formula to remove this obstacle."

Mottaki added that Iran was still interested in improving ties "in the fields of politics, economics and culture" with North Korea.

Kim said that his country would support Iran — under U.N. sanctions and locked in a diplomatic standoff with the West over its disputed nuclear program — on the international level, and that North Korea was ready to cooperate with Iran "in various economic fields."

The U.N. Security Council in 2006 imposed sanctions on both North Korea, after it conducted its weapons test, and Iran, for refusing to halt uranium enrichment.

North Korea has since refused to act on a February pledge to start dismantling its nuclear program in exchange for economic aid and political concessions.

Meanwhile, Tehran faces new, stepped-up sanctions for its refusal to halt the enrichment program, which Iran insists is peaceful and not for nuclear arms making.

Pyongyang has reportedly cooperated with Iran militarily since early 1980s, when Saddam Hussein waged an eight-year war against Iran. Officials of the two countries regularly meet each other.