The leaders of South Korea and Japan stood united Friday in saying North Korea should not be offered aid until the communist regime takes concrete steps to dismantle its nuclear weapons program.

The summit came days after North Korean leader Kim Jong Il said his country may rejoin international nuclear talks, depending on its negotiations with the U.S.

Despite the North's stated willingness to talk, Japanese Prime Minister Yukio Hatoyama said he backed South Korean President Lee Myung-bak's view on withholding aid to Pyongyang.

"We should not resume any economic assistance unless North Korea shows commitment and takes concrete steps" toward denuclearization, Hatoyama told a joint news conference with Lee.

Lee's proposal to offer a one-time "grand bargain" of aid and concessions in exchange for denuclearization -- rather than the step-by-step process pursued over the past six years -- is "completely correct," Hatoyama said.

Their stance emphasizes the skepticism Seoul and Tokyo share about the North, which is accused of raising tensions and then agreeing to dialogue and disarmament, only to backtrack after reaping the economic and political benefits of its promises.

Lee said he is confident North Korea will return to international nuclear talks after Pyongyang holds direct negotiations with Washington. He reiterated the need for a "fundamental and comprehensive solution" to the nuclear impasse to ensure that "past negotiating patterns will not be repeated."

Lee and Hatoyama left separately for Beijing later in the day for a three-way summit with Chinese Premier Wen Jiabao on Saturday, when Wen is expected to brief them on the outcome of his Monday talks with the North Korean leader.

Japanese Foreign Ministry Press Secretary Kazuo Kodama told reporters in Seoul that Tokyo will keep enforcing U.N. sanctions against North Korea while leaving the door open for discussion, saying an "approach of pressure and dialogue" is the best way to deal with Pyongyang.

Kim Jong Il's offer of dialogue reflects Pyongyang's desire for direct engagement with Washington. The Obama administration has said talks might be possible -- as part of the six-nation negotiations.

North Korea's deputy nuclear negotiator, Ri Gun, is seeking to visit the U.S. for a private security forum in California later this month, South Korea's Yonhap news agency reported Friday. Ri could meet with U.S. officials then to lay the groundwork for possible one-on-one negotiations, Yonhap said, citing an unidentified source.

The impoverished North withdrew from the six-party talks after being condemned for conducting a rocket test in April and a nuclear test in May. It said at the time it would never return to the disarmament-for-aid talks involving China, Japan, the two Koreas, Russia and the U.S.

The Seoul trip is Hatoyama's first visit to South Korea since he took office last month, though he met with Lee in New York on the sidelines of the U.N. General Assembly last month.

South Korea expects better ties with Japan under Hatoyama, who is considered more thoughtful than his conservative predecessors about historical sensitivities to Tokyo's invasion and occupation of the region before and during World War II.

Hatoyama reiterated Friday that he has the "courage to face up to history."

Japan ruled the Korean peninsula as a colony from 1910-45. While they are key economic partners, diplomatic relations between the two countries have been strained in the past after Japanese leaders made comments or engaged in acts seen as glorifying Japan's wartime past.