TOKYO (AP) _ Decades of antagonism resurfaced Tuesday as North Korea and Japan started talks on setting up official ties, with the North demanding compensation for wartime aggression and Tokyo urging information on suspected abductions.

The negotiations come amid an unprecedented series of diplomatic overtures by communist North Korea. But the blunt exchange of demands was a fresh reminder of how difficult it will be for the old enemies to reach an understanding.

North Korea's chief negotiator Jong Thae Hwa met with Foreign Minister Yohei Kono on Tuesday. A ministry official who was at the meeting, and spoke on condition of anonymity, said Jong told Kono that Japan's refusal to make amends for its 1910-1945 colonization of the Korean Peninsula was the main obstacle to closer ties.

Kono responded by reiterating Japan's long-held demand that Pyongyang aggressively investigate the suspected kidnappings of Japanese by North Korean agents in the 1970s, allegedly to serve as language teachers for spies. Jong repeated the North's denial of the abductions, the official said.

The talks in Tokyo, scheduled through Thursday, are the second round of negotiations begun four months ago in Pyongyang, North Korea's capital. Prior to that meeting, discussions had been suspended for eight years.

After the Kono-Jong talks, negotiating teams met for an hour and agreed to discuss details of their positions on Thursday.

Both sides expressed optimism because of thawing relations between democratic South Korea and the long-isolated North, following a June summit.

But Tuesday's talks echoed disagreements raised by Japanese and North Korean negotiators at the April talks in Pyongyang.

A Foreign Ministry official who briefed reporters on customary condition of anonymity said his impression was that the two sides haven't budged on the main issues.

Japan's top negotiator Kojiro Takano suggested that the kidnappings would have to be addressed in any eventual agreement in order to win the backing of the public and Parliament, the ministry official said.

Several relatives of the missing shouted ``Give them back,'' as the limousines of the North Korean delegation arrived.

Jong told Takano that North Korea remains immovable on its principal demands _ compensation and apology for the colonization, a return of cultural treasures allegedly taken by Japanese soldiers, and improving the legal status of Koreans living in Japan.

He hinted he still hoped for an agreement by the end of the year, set as a target by both parties.