The board of education of the Hiroshima prefectural government is demanding 108 school teachers submit reports over their refusal to stand while the national anthem was sung at entrance ceremonies in public schools in April, the school teachers said Sunday.

The prefectural education board has been asking the elementary, junior high and senior high school teachers to submit reports stating the reasons for their acts and showing remorse, the teachers said. The union of school teachers reacted angrily to the board's move, however, saying it encroaches on free thinking and forces the use of "Kimigayo," the de facto national anthem.

According to the board, 60 teachers in prefecture-run schools and 48 teachers in municipal-run schools refused to stand for the national anthem. The education board had earlier instructed teachers to stand while the national anthem is sung at graduation and entrance ceremonies.

The education board reprimanded 194 teachers who failed to stand for the national anthem at graduation ceremonies in March. The board is likely to take similar disciplinary measures against the 108 teachers this week, the teachers and school sources said.

In a related development, the education board also called for the principals of the schools where the 108 teachers work to submit reports on their guidelines for education from now on, the sources said.

The de facto national anthem of Japan is criticized by some as eulogizing the emperor and symbolizing the imperialism of the period up to the end of World War II, along with Japan's "Hinomaru" national flag.