In its 2020 designation of official John Lee, the US Treasury Department said he had been involved in the 'coercing, arresting, detaining, or imprisoning' of people in the Chinese city who had protested against the law.

The summits have been attended by global leaders, and the talks have often been disrupted by friction spilling over from the war in Ukraine as well as flashpoints such as the Taiwan strait and the Korean peninsula.

Addressing a summit in Bangkok, Harris called the US a 'proud Pacific power' and said that the longstanding US network of security alliances has allowed Asia to prosper.

About 350 protesters had gathered and clashed with police, about 10km from the venue where leaders of the Asia-Pacific Economic Cooperation group are meeting.

The Thai prime minister urges participants at the Apec summit to seek sustainable growth and development after economic and social challenges from Covid, climate change and geopolitical rivalries.

While Thailand hopes to make progress on forming a Free Trade Area of the Asia Pacific, the talks come amid geopolitical tensions over the war in Ukraine and other flashpoints such as Taiwan and the Korean peninsula.

Since Thailand decriminalised cannabis this year shops selling homegrown and imported strains, pre-rolled joints and gummies sprang up rapidly.

Leaders from the Association of Southeast Asian Nations will meet in Phnom Penh, kicking off a diplomatic blitz in the region that also takes in next week's G20 in Bali and an Apec summit in Bangkok.

New Zealand Prime Minister Jacinda Ardern says there is also a determination to cut tariffs on vaccines and associated medical equipment.

China says it has already supplied developing countries with more than 500 million Covid-19 vaccine doses.

This is the first time in Apec's history that leaders have had an additional meeting at this level, she says.