European allies see two sides of Trump

In Sicily, Donald Trump listened attentively during complex G7 debates over trade and climate change, smiled for the cameras, and for the most part refrained from provocative tweets.

In Brussels, he bashed NATO partners for not spending more on defense, shoved the prime minister of Montenegro and renewed his attacks on Germany's trade surplus with the United States.

America's allies witnessed the two sides of Trump on his first foreign trip as US president, a nine-day tour that began with sword dancing in Saudi Arabia and vague pledges in Israel to deliver Middle East peace.

As Trump headed home, European officials were left with mixed feelings: relief that he had been patient enough to listen to their arguments and unsettled by a Jekyll-and-Hyde figure who is still finding his way on the big policy issues.

"It all fits with his strategic ambiguity approach to life," said Julianne Smith of the Centre for a New American Security. "It may do wonders when dealing with adversaries. But it doesn't work when dealing with allies," she said.

Other leaders of the Group of Seven nations had viewed with trepidation their summit, held at a cliff-top hotel overlooking the Mediterranean, after four preparatory meetings failed to clear up differences with the Trump administration on trade, how to deal with Russia and climate change.

But in the end, officials said, the result was better than they had feared.

The final communiqué acknowledged a split between the United States and its six partners over honoring the 2015 Paris accord on climate change. That followed a debate with Trump that German Chancellor Angela Merkel described as "very dissatisfying".

However on trade, Trump bowed to pressure from allies to retain a pledge to fight protectionism. And on Russia, he did not insist on removing - as some allies had feared - the threat of additional sanctions for Moscow's intervention in Ukraine.

"I found him very willing to engage, very curious, with an ability and desire to ask questions and to learn from all his interlocutors," said Italian Prime Minister Paolo Gentiloni, the G7 summit's host.