Trump went into the G-7 summit having riled its other members - Canada, Britain, France, Italy, Germany and Japan - on a number of geopolitical issues. But it won't solve the differences, particularly on trade, with the European Union moving toward retaliatory tariffs from July on key US goods. But differences remain on how to balance French President Emmanuel Macron's call for more solidarity in Europe.
The UK prime minister expressed disappointment over USA decision to tax steel and aluminum imports from the European Union.
A White House adviser later admitted that Trump's desire to appear strong was partly the reason for this move.
While there was "common ground" in some areas, she said she was "disappointed" by the USA stance on trade.
He said USA farmers had been harmed by tariffs and other barriers and warned that USA trading partners would need to provide him with more favorable terms: "It's going to stop or we'll stop trading with them".
A German official said that if Trump declines to sign a communique, it won't be the end of the G-7, but it would be a worrisome signal.
Turning to Russia, Merkel said she could imagine Moscow re-joining the G7 format at some point, but not before Russian President Vladimir Putin fully implements the peace plan for Ukraine by withdrawing his occupation forces back across to the Russian side of the border. "They don't take our farm products", Trump complained at the news conference Tuesday.
The British leader echoed disappointment from other leaders that President Donald Trump first agreed to a communique for "free, fair and mutually beneficial trade" and the reduction of "tariff barriers", but later tweeted he wouldn't endorse the deal.
Other photos from the summit show Merkel and Trump in conversation. He explained that "with regret", Canada will impose "equivalent" retaliatory tariffs on the US, effective July 1. "International cooperation cannot depend on anger or small words".