Analysts here are undecided whether the killing was accidental or intended to cast blame on the South's new conservative government, which has rejected the appeasement policies of previous administrations.
The North's liaison officer at the truce village of Panmunjom refused to answer repeated phone calls from the South, according to the Unification Ministry here.
Pyongyang's uncooperative attitude fueled suspicions about the intentions of the North's hard-line military, which fears expanded cross-border contacts could weaken its authority.
A security source said the North's troops may have been ordered to respond decisively to any security violations by South Korean tourists.
Such measures have often been taken by Kim Jong-Il's regime to tighten its control over the population during worsening economic and food conditions.
Pyongyang rejected last week's proposal by South Korean President Lee Myung-Bak to resume stalled inter-government reconciliation talks, calling it a "deceitful" tactic to avoid taking responsibility for strained ties.
Officials in Seoul said the shooting death and the North's refusal to allow an investigation by the South could boost Pyongyang's image as a state sponsor of terrorism and interrupt plans by the U.S. to remove North Korea from its terrorism blacklist, again stalling the denuclearization process.
The nuclear deal could also lose steam due to the North's refusal to comply with Japan's demand that the issue of North Korean abductions of Japanese nationals during the 1970s and 1980s be resolved.
Japan's Prime Minister Yasuo Fukuda made clear that his country would not fulfill its part of the six-nation aid-for-denuclearization deal and lift sanctions against North Korea, saying Pyongyang has not followed through on a promise to reopen its investigation into past abductions of Japanese citizens.
