Japanese Prime Minister Shinzo Abe sent a ritual offering Wednesday to Yasukuni Shrine, viewed as a symbol of Japan's wartime militarism by neighboring countries, on the first day of its four-day autumn festival.

Abe has refrained from paying tribute in person at the shrine in central Tokyo since late 2013.

The prime minister's ritual offering to the shrine which honors the nation's war dead came at a time when relations between Japan and China have been improving. This year also marks the 40th anniversary of a bilateral peace and friendship treaty taking effect.

"We urge Japan to faithfully face up to its history of aggression and deeply reflect upon it," Chinese Foreign Ministry spokesman Lu Kang said at a regular press briefing in Beijing, adding Japan should "win the trust of Asian neighbors and the international community with actual action."

In Seoul, an official of South Korea's foreign ministry expressed "deep concern" over the offering, adding that the shrine "beautifies Japan's history of militaristic aggression and colonial rule."

Visits by Japanese leaders to Yasukuni have angered in particular China and South Korea, both of which suffered from Japan's past aggression, as it honors convicted war criminals, including wartime prime minister Gen. Hideki Tojo, along with more than 2.4 million war dead.

This time, however, China only repeated the same mantra about Abe's latest move, apparently taking into consideration recent improvement in ties with Japan and the prime minister's planned three-day visit to Beijing from Oct. 25.

The Japanese prime minister is scheduled to hold talks with Chinese President Xi Jinping on Oct. 26 to discuss ways to develop relations between the two Asian powers.

Abe, who is on a foreign trip to attend a meeting of Asian and European leaders, made the "masakaki" tree offering under the name of the prime minister, according to the shrine. The tree is typically used in Shinto-style rituals.

Backed by conservative supporters, Abe has regularly delivered ritual offerings to the Shinto shrine during its spring and autumn festivals and given ritual donations on Aug. 15, the anniversary of Japan's surrender in World War II.

On Wednesday, welfare minister Takumi Nemoto, House of Representatives Speaker Tadamori Oshima, and House of Councillors President Chuichi Date also separately offered masakaki.

Abe's visit to the shrine in December 2013 further soured relations between Japan and China, which were already at odds over a group of Japan-controlled islets claimed by Beijing in the East China Sea.