Former Swedish prime minister Carl Bildt wrote a tweet Monday ripping Sen. Bernard Sanders for a resurfaced video of the democratic socialist praising the Soviet Union in 1988.

Mr. Bildt’s tweet included the video of Mr. Sanders, then-mayor of Burlington, Vermont, giving a speech following a recent trip to the Soviet Union, where he said he was “extremely impressed” by the public transportation system.

“The stations themselves were absolutely beautiful, including many works of art, chandeliers that were beautiful. It was a very, very effective system,” Mr. Sanders said in the video. “Also, I was impressed by the youth programs that they have. There are palaces of culture for the young people — a whole variety of programs for young people and cultural programs which go far beyond what we do in this country.”

Mr. Bildt, who served as Sweden’s prime minister from 1991 to 1994, tweeted in response: “Bernie Sanders was lucky to be able to get to the Soviet Union in 1988 and praise all its stunning socialist achievements before the entire system and empire collapsed under the weight of its own spectacular failures.”

This isn’t the first time Nordic leaders have fired back at Mr. Sanders, a democratic socialist who often cites countries such as Sweden and Denmark as successful welfare states that help “working people.”

In 2015, Denmark Prime Minister Lars Lokke Rasmussen slammed Mr. Sanders for associating his country with socialism.

“The Nordic model is an expanded welfare state which provides a high level of security to its citizens, but it is also a successful market economy with much freedom to pursue your dreams and live your life as you wish,” Mr. Rasmussen said at the time, Independent Journal Review reported.