A bipartisan group of lawmakers friendly to China has canceled a trip planned for early May because of difficulties arranging meetings with President Xi Jinping and other senior officials, a source within the group said Monday.

The source said it is unclear whether a visit over the weekend to the war-related Yasukuni Shrine in Tokyo by Deputy Prime Minister Taro Aso and two other Cabinet ministers, as well as a ritual offering sent to the shrine by Prime Minister Shinzo Abe, led to the cancellation.

Yasukuni honors convicted Class-A war criminals from World War II along with Japan’s other war dead. Over the years, visits to the shrine by prime ministers have angered China and South Korea, both of which were invaded by the Imperial Japanese Army during the war.