In comments to Polish state news agency PAP, Wałęsa said: “How can a first citizen be elected with such a resumé and such actions?”

The Polish 1983 Nobel Peace Prize winner said the U.S. had previously set the world a good example but was now “showing something incredible.”

Trump, whose legal travails have not stopped him from returning to the White House, will be the first convicted felon to hold the country's highest office.

The Republican president-elect has in the past praised Wałęsa, the leader of the Solidarity trade union’s protests in the 1980s against Poland’s communist authorities.

Asked what a Trump victory meant for the West, NATO and Ukraine, Wałęsa replied: “We can’t foresee that because with someone with such a character, with such a resumé, you don’t know what to expect.”

‘Fuel’ for Polish rightwingers?

Another former Polish president, Aleksander Kwaśniewski, who was head of state from 1995 to 2005, said Trump’s victory could “fuel” the right wing in Poland.

Kwaśniewski, a leftist, said the nationalist-populist Law and Justice (PiS) party, which ruled for eight years before being ousted last October, may use its close ties to Trump to its advantage in next year’s presidential election in Poland.

“This won’t determine the outcome, to be clear, but I believe it will be one of the main topics in what promises to be a particularly tough and intense presidential campaign – the likes of which we haven’t seen in recent years,” Kwaśniewski said in an interview for private broadcaster Radio Zet.

PAP reported that the PiS leader, Jarosław Kaczyński, had expressed satisfaction at Trump’s victory.

Meanwhile, in a separate interview for the TVN 24 private television channel, Kwaśniewski concurred with Wałęsa.

“Trump is unpredictable, even according to his own supporters and collaborators,” he said, adding that this made it hard to predict what his administration might hold.

Kwaśniewski also called on the current Polish president, Andrzej Duda, to brief Trump on the situation in Ukraine and the region, stressing the need for the U.S. president-elect to have “credible information” on the subject.

Kwaśniewski called on Duda, whose term ends next year, to engage in a “last mission, a last dance” for the good of Poland and Ukraine.