Calls are on the rise for Japanese Prime Minister Shinzo Abe to make a sincere apology prior to a statement by Abe to mark the 70th anniversary of the end of WWII.

"Japan's barbarities are globally known and have been ascertained by international courts," said Natalino Ronzitti, an emeritus professor of international law at LUISS University in Rome and an advisory expert for the Rome-based Institute of International Affairs (IAI).

"Historical memory is important in order to help progress and avoid that certain brutalities will happen again," he said.

Increasing commercial exchange and economic ties between China and Japan could not erase the complexity of the 20th century, a century in which the Japanese expansionism was marked by a violent aggressiveness against all peoples of East Asia, noted Davide Rossi, a historian and director of the Locarno-based ISPEC Institute of History and Philosophy of Contemporary Thought.

"The dead, the massacres, the destroyed villages, torture, reduction in slavery of women and men from China and other Asian nations are a wound that Japanese governments have made amends for over the years, but that unfortunately Abe's nationalism is trying to elude," Rossi told Xinhua.

Abe is expected to make a statement on Friday to mark the 70th anniversary of the end of World War Two (WWII).

The statement is closely watched by the world, especially the Asian countries which suffered immensely during the war due to the Japanese invasions.

South Korean Foreign Minister Yun Byung-se said the South Korean government repeated demand for the Abe statement to completely and clearly inherit the perception of history shown in previous statements issued by former prime ministers.

If Abe does so, relations between South Korea and Japan would be pushed forward with a strong force, Yun said, wishing that true rapprochement would take root in the Northeast Asian region.

South Korea has called on Abe to include four key words, including war of aggression, colonization, apology and remorse, in his statement, inheriting historical perceptions reflected in former prime ministers' statements by Tomiichi Murayama in 1995 and by Junichiro Koizumi in 2005.

UN Secretary General Ban Ki-moon has also urged Japan to reflect on its war history in order to move forward ahead of the Abe statement.

The country "should move forward for a better future through genuine reconciliation and in the spirit of cooperation based on humble reflection of past history," said Stephane Dujarric, a spokesperson for Ban.

The Bloomberg said in a Thursday report said Japan's relations with its neighbors have been soured by Abe's drive to strengthen the military.

"On the 70th anniversary of his nation's World War II surrender, Abe's challenge is to keep his nationalist base on side, while showing enough remorse to enable a further thaw" in ties with its neighbors, it said.

"After 70 years, a painful chapter in the region's history should have been closed by all who contributed to and bore the anguish of World War II," said an editorial of the Straits Times in Singapore.

"The weight of history and his own past actions place that duty on Japanese Prime Minister Shinzo Abe too," when he makes his statement to mark the anniversary, it said.