North Korea is upset that Japanese Prime Minister Naoto Kan only mentioned South Korea in Tuesday's apology for colonial rule, the Kyodo news agency reported Wednesday.

It quoted a North Korean official in charge of Japanese affairs as saying, "We can only conclude that Japan wants to maintain the division of the peninsula. Even 65 years after the end of World War II, Japan has failed to settle the past with our country."

The North "has the right to demand that Japan settle issues stemming from its colonial rule," another North Korean official said and urged Tokyo to "take action as early as possible."

Japan and North Korea have no diplomatic relations.

Japanese experts say any apology to and compensation for North Korea will need fresh discussions as the two countries continue the slow process of negotiating the establishment of formal relations.

Domestic political concerns seem to have been another reason why Japan did not mention the North in the apology.

"Japanese rightwingers were already upset by the statement," one expert said. Tokyo apparently worried that "if it had apologized to the North as well, the statement would have attracted even fiercer resistance given the deeply negative view Japanese people have of the communist country" due to the North's bizarre abduction campaign of Japanese citizens in the 1970s and 80s.