Bildt made the comments in an interview with US news site Politico, pointing out that Putin is "to put it mildly, a somewhat more experienced player" than the US President, and adding that it will be interesting to see when the two meet for the first time "whether Putin will take Trump for a ride. That is not to be excluded".
The Swede highlighted the '10 minute history lesson' on China and Korea that Chinese leader Xi Jinping gave Trump in an April meeting, and noted that Putin is clearly "going to try to do the same thing in trying to influence a man who doesn't have very many core convictions. So that is still a point of worry where that ends up".
Bildt, an outspoken critic of Trump who once pondered what the American might have been smoking when he made his infamous "last night in Sweden" comments, told Politico that Swedes were both irked by the US President's attacks on the Nordic nation as well as entertained.
"People were appalled and then there was an element of sort of entertainment. They thought the man had gone bananas, one way or the other. They couldn't begin to understand it."
"It was a somewhat unsettling thing to see the president of the United States without any factual basis whatsoever lunge out against a small country in the way that he did," he added.
In February, Trump controversially suggested a serious incident had taken place in Sweden "last night", much to the confusion of Swedes, who wondered what he meant after an uneventful evening in the country.
The US leader later clarified that he was referring to a Fox News report which incorrectly claimed crimes like rape had risen sharply in the country after the 2015 refugee crisis.
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