German Chancellor Angela Merkel has sharply criticised US policy under President Donald Trump for being based on a "winners and losers" view of the world rather than on cooperation.
Ms Merkel will host the two-day meeting of G20 leaders that starts on Friday in Hamburg.
Along with Mr Trump, others attending include Russian President Vladimir Putin and Turkey's Tayyip Erdogan.
Getting ready to leave for Poland, after which I will travel to Germany for the G-20. Will be back on Saturday.
— Donald J. Trump (@realDonaldTrump) July 5, 2017
The talks are expected to be tricky as the agenda includes divisive issues such as free trade and climate change.
"As G20 president, it is my job to work on possibilities for agreement and not to contribute to a situation where a lack of communication prevails," she told Die Zeit weekly.
However, she added that differences should not be pushed under the table.
"While we are looking at the possibilities of cooperation to benefit everyone, globalisation is seen by the American administration more as a process that is not about a win-win situation but about winners and losers," she said.
The United States made some of the worst Trade Deals in world history.Why should we continue these deals with countries that do not help us?
— Donald J. Trump (@realDonaldTrump) July 5, 2017
She said comments from a Mr Trump security adviser that the world was an arena, not a global community, contradicted her views.
Germany wants everyone to benefit from economic progress rather than only a few, she said.
Europe must pool its energy, she said, adding that ideas of an economic government for the eurozone and of a European finance minister, put forward by new French President Emmanuel Macron, were "two important thoughts".
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Meanwhile, German police used water cannon to disperse around 500 anti-capitalist protesters overnight in Hamburg.
Tens of thousands of protesters are expected to march in the city this week against globalisation and what they say is corporate greed and a failure to tackle climate change.
German authorities believe around 8,000 demonstrators were prepared to use violence, the interior minister said yesterday.
20,000 police officers will be deployed.
Hundreds of activists gathered and marched on a main street shortly before midnight in the first major protest ahead of the summit.
Der Spiegel magazine reported that the German army fears protesters will use unarmed drones and that it has deployed a radar to locate any possible aerial intrusions.
A spokesman for the German military declined to confirm the report.
