Dozens of protesters hold signs and posters urging visiting Japanese Prime Minister Shinzo Abe to look squarely at history and apologize for the crimes committed by Japan during the World War II as Abe delivers a speech at the Harvard University in Cambridge, the United States, April 27, 2015. [Photo/Xinhua]

CAMBRIDGE, the United States - Dozens of protesters on Monday shouted "Abe must apologize!" as visiting Japanese Prime Minister Shinzo Abe delivered a speech at the Harvard University.

The protesters, mainly students from the prestigious university and Korean Americans, held signs and posters urging Abe to look squarely at history and apologize for the crimes committed by Japan during the World War II.

One sign read: "History can be rewritten. The Truth cannot." Another asked Abe to "stop denying" and called for "unequivocal apology now."

Abe arrived in Boston on Sunday, kicking off his week-long visit to the United States that includes a summit with US President Barack Obama and a speech to a joint session of Congress. His attitude toward history has strained Japan's ties with neighboring countries including China and South Korea.