High tension G20 opens, dominated by Trump quarrels

G20 powers open two days of summit talks on Friday after a stormy buildup dominated by tensions with Russia and US President Donald Trump's combative stance on trade and climate fears.

Trump and his Russian counterpart Vladimir Putin will be among the world leaders gathering amid high tension over an array of world issues including the Ukraine conflict, trade with China and relations with Saudi Arabia.

But the two will not sit down together after Trump abruptly cancelled a planned meeting, citing Russia's recent seizure of Ukrainian ships and sailors.

Protesters have vowed mass rallies to harangue the world leaders gathering in crisis-hit Argentina, where recent violence between rival football fans raised questions about the police's ability to control unrest.