China slammed Japan after Prime Minister Shinzo Abe’s wife paid a visit to the controversial Yasukuni Shrine in central Tokyo.

A spokesman for China’s foreign ministry called on Japan to “deeply reflect” on its history after Akie Abe visited the memorial, which honors Japan’s war dead. The Yasukuni Shrine commemorates Japanese soldiers who have died during active service since the 19th century, including a number of war criminals, according to AFP.

China Criticizes Japan As Abe's Wife Visits War Shrine

War criminals honored by shrine, angering China

Over a dozen of those honored by the shrine have been convicted of war crimes by the International Military Tribunal for the Far East, a fact which upsets China. Foreign ministry spokeswoman Hua Chunying criticized Japan for its failures in addressing its violent history.

Japan should earnestly look squarely at its past history of aggression and deeply reflect on it, thoroughly separate itself from the militarism of the time, make more efforts that will help enhance mutual trust and achieve reconciliation with neighboring countries in Asia,” she said in a post on the foreign ministry website.

Abe later uploaded photos to her Facebook page after visiting the monument. “I feel different about Yasukuni after a visit to Chiran,” she wrote, in reference to a base used by suicide mission pilots in World War II.

Japan has not issued formal apology for war atrocities

Prime Minister Abe did not visit the shrine himself, but a number of Cabinet ministers were seen at the site on Saturday, which marked 70 years since Japan surrendered during World War II.

On Friday, Abe released a statement on the war which was roundly criticized by China and South Korea. Both nations were disappointed that Abe did not issue a proper apology for Japan’s aggression during the war.

Wrangling over the war and its causes are an ongoing issue between China and Japan, and tensions have escalated of late. Maritime territorial disputes are another cause for concern, and constitute a major obstacle to normal relations between the two biggest economies in Asia.

Maritime disputes add to contemporary tensions

Japan has grown increasingly concerned by Chinese land reclamation programs in the South China Sea, and the construction of oil and gas installations in the East China Sea. The Senkaku/Diaoyu islands have been a cause of tension for years, but recent Chinese efforts to build new surveillance ships and deep sea ports to increase its presence near the islands have caused concern in Japan.

Prime Minister Abe previously expressed an interest in joining international patrols in the South China Sea, where the U.S. Navy has been caught up in tense standoffs with its Chinese counterpart. Regional concern over China’s activities in the vital shipping lane are growing, and as a trading nation Japan has an interest in maintaining freedom of movement.

Abe’s pronouncements on the patrols provoked opposition from China, which warned Japan to stay out of the area. As it stands, Japanese laws prevent the country’s Self Defense Force from engaging in patrols such a distance away from Japanese waters, but Abe is pushing for amendments to the pacifist constitution.

As China continues to push for more influence in Asia, it seems inevitable that relations between the two nations will become strained. China is still waiting for a formal apology from Japan regarding World War II, and at the moment it seems that Beijing is not willing to forget that fact.