CHONGQING -- Japan's former prime minister Yukio Hatoyama apologized for his country's bombardment of Southwest China's Chongqing during World War II at the 2016 China International Friendship Cities Conference Thursday.

Hatoyama made the apology at the opening of the conference in Chongqing, the wartime capital of the Kuomintang government, where Japanese air-strikes from 1939 to 1941 left more than 30,000 people dead or injured.

In his speech, Hatoyama criticized Japanese Prime Minister Shinzo Abe for inflating the "China threat", noting that such remarks will bring tension to the region. He said that an East Asian Community with China, Japan, South Korea and ASEAN at the center would reduce nationalism.

Friendship cities are important in communication between countries, he said, adding that political, economic and cultural exchanges alleviate conflict and promote integration.

Over 700 representatives from around the world joined this year's conference.