TOKYO, Jan. 4 - Prime Minister Junichiro Koizumi squarely blamed China and South Korea on Wednesday for worsening relations with Japan, accusing them of interference in Japan"s domestic matters.

In a nationally broadcast news conference for the new year, Mr. Koizumi defended his annual visits to the Yasukuni Shrine, the memorial to Japan"s war dead, although the visits have frozen Japan"s diplomatic relations with its neighbors. The leaders of China and South Korea have refused to meet Mr. Koizumi as a protest over his visits to the shrine, which also honors top-ranked war criminals and is considered a symbol of Japanese militarism in Asia.

"I can"t understand why foreign governments would intervene in a spiritual matter and try to turn it into a diplomatic problem," Mr. Koizumi said, adding that he visited the shrine to pray for peace.

The comments, which drew immediate condemnation from Seoul, came as Tokyo and Beijing are embroiled in a bitter dispute over the suicide of a Japanese diplomat in Shanghai in 2004. The remarks amounted to another sign that after a year of rising tensions and Japan"s growing estrangement from the region, all sides appeared to be hardening their positions.

South Korea"s foreign minister, Ban Ki Moon, responded to Mr. Koizumi by saying bluntly that Japan"s leaders needed a "better understanding of history" and should earn the "trust and respect of other countries." Because of the Yasukuni dispute, South Korea"s president, Roh Moo Hyun, did not visit Japan last year, as he had in previous years.

There was no immediate comment from Beijing.

The growing rivalry between China and Japan was punctuated in recent days by the feud over the diplomat"s suicide. A Japanese newsweekly reported recently that the diplomat killed himself after he was blackmailed into providing secret information by a Chinese agent who threatened to reveal his affair with a bar hostess.

The Japanese Foreign Ministry attributed the death to "regrettable actions by local Chinese security authorities" in violation of the Vienna Convention on Diplomatic Relations. China denied the charge, accusing Japan of trying to "smear China"s image."

Mr. Koizumi"s tough talk tapped into a growing resentment and fear of a rising China among ordinary Japanese. Business and personal exchanges are greater than ever, as Mr. Koizumi himself pointed out, but the diplomatic friction has also begun to change public opinion.

According to a government survey released at the end of last year, only 32.4 percent of Japanese said they had "friendly feelings" toward China. The figure, down 5.2 percentage points from the previous year, was a record low.

Japanese public opinion also grew less favorable toward South Korea, with 51.1 percent expressing positive sentiments, down 5.6 points from the previous year. Japan"s positive feelings toward South Korea had increased annually in the previous four years, reflecting improving ties, which took a turn for the worse last year over Yasukuni and other issues.