Foreign Minister Taro Aso's suggestion to undertake joint economic projects with Moscow on four Russian-held islands off Hokkaido that are claimed by Japan completely caught some ministry officials off guard Friday.

At a news conference, Aso said he had told several reporters Wednesday that the two sides cannot break the deadlock if they simply stick to their positions on the issue of sovereignty over the islands.

Aso's remark led to a headline in a major newspaper Thursday that he had proposed the idea in a meeting with Russian Foreign Minister Sergei Lavrov on the sidelines of the Asia Pacific Economic Cooperation forum in Pusan, South Korea, on Wednesday.

Although Aso denied that he made such a proposal during his meeting with Lavrov, he said the idea may be worth considering.

"By carrying out joint projects, a trusting relationship will be nurtured between Japan and Russia," Aso said. "It will also improve the standard of living of local residents."

But he said he has not shared his idea with ministry officials.

A top ministry official, who asked not to be named, said Aso's remark was not the product of a careful and thorough discussion within the ministry and added that it would not be on the agenda of the summit between Prime Minister Junichiro Koizumi and President Vladimir Putin scheduled for Monday.

The official said that it may be tactically possible to begin joint economic development on the islands without touching on the issue of sovereignty.