The 21st Association of Southeast Asian Nations (ASEAN) Plus Three Summit held here on Thursday called for collective efforts of members to tackle common challenges and maintain multilateralism.

Singaporean Prime Minister Lee Hsien Loong, whose country holds the rotating ASEAN chairmanship this year, hosted the summit which groups ASEAN and its three external partners of China, South Korea and Japan.

"We must continue to maintain an open, rule-based and inclusive global trade environment" for all members, said the prime minister in his opening remarks, adding that the group should redouble its efforts to uphold the multilateralism so as to tackle the common challenges of growing trade tensions, digital revolution and cyber security.

Lee hailed that the group has made impressive progress in fighting against SARS in 2003 and global financial crisis in 2008, adding that trade flows amongst the group also accelerated drastically.

The efforts are "transforming East Asia into one of the world's most prosperous regions," the prime minister said.

He noted that ASEAN's trade in goods with the three countries totaled over 800 billion U.S. dollars, accounting for some 31 percent of ASEAN's merchandise trade in 2017.

The ASEAN Plus Three summit is considered as a main channel for the cooperation in the East Asia, aiming at regional economic integration in different domains such as culture, education and exchanges between youths.

The mechanism began in late 1997 and was institutionalized in 1999. ASEAN is a regional group including countries of Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam.