It began with two cans of tomato soup.

In mid-October, two climate activists wearing "Just Stop Oil" T-shirts opened the cans and threw tomato soup onto Vincent van Gogh's famous painting "Sunflowers" in London's National Gallery. Then, they glued their hands to the wall below the painting.

Climate activist groups intent on raising awareness have attacked/vandalized more than 15 artworks in Europe, Australia and Canada this year — more than five in the past month alone. On Nov. 18, climate activists from the Last Generation dropped about 18 pounds of flour on a car decorated by Warhol in Milan. On Oct. 23, they threw mashed potatoes at a Monet in Potsdam, Germany, and on Nov. 15, they spilled black liquid onto Gustav Klimt's "Tod und Leben" in Vienna.

Ninety-two museum directors around the world, including Minneapolis Institute of Art Director and President Katie Luber, have signed a statement condemning the actions. "As museum directors entrusted with the care of these works, we have been deeply shaken by their risky endangerment," the statement reads.

The performative vandalism of prized artworks at international museums worldwide has put many directors on heightened alert. Twin Cities art museum directors shared little information about their security measures. Local museum directors couldn't recall any recent art vandalism.

"In the early '80s and '90s, museums didn't want to talk about anything. They tried to keep it from the press," said John Barelli, former director of security at the Metropolitan Museum of Art in New York and author of "Stealing the Show: A History of Art and Crime in Six Thefts."

"It's a cautious subject," American Swedish Institute President and CEO Bruce Karstadt said. "I'm not sure anyone is going to be specific about their security arrangements."

At ASI, they use an integrated security system, which includes technology, staff and volunteers, Karstadt said, and the institution has upgraded its systems.

Karstadt said that in the 32 years he has been at ASI, he doesn't recall any vandalism.

"I think on one occasion we found that someone had stolen one of those plastic cases where you drop money to make a donation," he said. "But no artwork has been damaged."

It was a similar response at the Museum of Russian Art (TMORA). According to an article published April 7, someone broke into the museum and stole cash from a donation box, but Executive Director and President Mark Meister said no artwork has ever been vandalized at TMORA.

"We've improved our CCTV perimeter security," he said, "but you know, you basically have to trust in the goodwill of the visitor."

Certain works are protected under glass or plexiglass, but paintings are mostly visible so that viewers can appreciate them.

"There's a difficulty in balancing the appropriate experience for the viewer to appreciate the works versus the need of the museum to protect the work," Meister said. "Museums do things like putting up ropes to keep you a few feet away."

Although Mia's Luber was one of 92 directors to sign the international letter decrying the climate activists' attacks on artworks, she declined to comment further.

"We are obviously aware of what's happening, and we do have security measures in place, and we're making sure we keep the art and the visitors and the staff safe," Mia's Chief Audience Officer Kristin Prestegaard said.

Although Prestegaard would not go into any security measure details, she said there were extra security guards at the Botticelli show on exhibit now at Mia.

"Whenever we have a loaned exhibition, the agreement is that there is a guard or two in each gallery," she said. "Of course we are reading the news, but these are security measures we have always had in place, so nothing is escalated for this."

Rachel Joyce, assistant director of public relations at the Walker Art Center, said: "Our security director said that our rigorous security protocols that are already in place prepare the staff for gallery disruptions. Due to the sensitive nature of museum security, I cannot offer you detailed information."

Joyce also said that, according to the office of the registrar, they "have not had any of our works tampered with. Visitors are respectful of the art and if there are safety concerns, we use stanchions."

Gwen Sutter, associate director at the Weisman Art Museum, said that some of the most frequent acts of vandalism are totally accidental.

"If people have water bottles or, you know, any sort of food items, we ask them to leave them at the desk, where they can pick them up on their way out," she said. "We asked them to carry their backpacks either in front of them or alongside because sometimes people don't realize how wide they are… and sometimes they bump into something."

Security at the Weisman is mostly students, so they are trained in-house. That includes sensitivity training.

"We do think one of the barriers we hear a lot from some of the focus groups we've done is that a lot of students have never been to a museum before and so they don't know how to act," Sutter said. "So by having students greet them when they walk in the door, we think that provides a friendlier entrance for them."

Barelli explained that the Sept. 11 attacks, which happened in New York during his time at the Met, changed museum security.

"There's two things that really helped cut down the vandalism," Barelli said. "After 9/11, we instituted bag checks for everybody coming in. ... You'd even see people say 'I'm not even going in,' because [security] would check not only for weapons or bombs ... [but also for] anything like paint, scissors, knives, that type of thing."

Technology, particularly video imaging camera systems that tape the galleries 24/7, also has changed the way people behave in the galleries.

"It was a great deterrent," he said. "People would look and see if there were cameras in the galleries."

Erin L. Thompson, an art crime specialist who writes extensively on art theft and vandalism, said that museums unwittingly allowing people to bring in certain foods is part of the problem in these ongoing attacks by climate change activists.

"It just shows a failure of museum security," she said.

It remains to be seen whether museum security in general will change as a result of recent international incidents.

"My counterintuitive point was like OK, maybe stuff like this is going to spur more entrance security," Thompson said. "Which already happens in some museums in some places, and even in the United States, like if you go into any Jewish Heritage Museum, there is definitely a metal detector."

However, in Minneapolis, museum directors said that art vandalism hasn't been an issue.

"No, not [during] my time here," said Meister, who started at TMORA in October 2019. "No vandalism toward works of art whatsoever. You know, it's very, it's just very, very rare that it happens."