HELSINKI — Carl Fredrik Reutersward, one of Sweden’s best-known modern artists and the creator of the iconic statue of a revolver barrel tied in a knot, has died at the age of 81.

The artist, who was a major influence in the modern Swedish art scene, died in a hospital in Helsingborg, southwestern Sweden, Tuesday evening, Thomas Millroth, from the Carl Fredrik Reutersward Art Foundation, said. He gave no cause of death, but Mr. Reutersward, who suffered a stroke in 1980, was known to have been unwell for some time.

“He was instrumental in establishing contacts with the art scene in New York where everything was happening at an important time,’’ said Daniel Birnbaum, director of Stockholm’s Moderna Museet, adding that Mr. Reutersward’s circle of friends included Andy Warhol, Jasper Johns, and Robert Rauschenberg, and his works were exhibited in various museums, including MOMA in New York City in the 1970s.

“[He] was close friends with American artist[s] of his generation, but was a very European artist himself and, I think, was perceived as such by his US friends,’’ Birnbaum said. “He was obviously better known in the world than we have understood here in Sweden.’’

Born in 1934 in Stockholm, Mr. Reutersward was a poet as well as a painter and sculptor, who studied in Paris in 1951 under Fernand Leger, the French painter and sculptor widely regarded as a forerunner to pop art. He held his first exhibition the following year in Paris but returned to Sweden to continue his studies at the Academy of Fine Arts in Stockholm where he held a professorship in painting from 1965 to 1969 until he moved to Switzerland.

In 1974, he was awarded the position of guest professor at the Minneapolis School of Art.

Mr. Reutersward, who became acquainted with John Lennon and Yoko Ono in Switzerland in 1969, was shocked by the 1980 shooting of the former Beatle.

“I was filled with bitterness and anger and immediately began to create a symbol for John Lennon and everyone else who has been a victim of such assassins,’’ he wrote after Lennon was shot outside his apartment in New York.

The twisted gun statue, which he called “Non Violence,’’ became an international symbol of peace the world over. One version of it sits outside the UN building in New York, with others in various cities around the world, including Los Angeles; Berlin; Stockholm; Caen, France; and in Luxembourg.

Swedish Foreign Minister Margot Wallstrom tweeted in reaction to his death: “His sculpture outside the UNHQ reminds us that peace is the only way.’’

After his stroke, Mr. Reutersward was partially paralyzed, forcing the right-handed artist to draw with his left hand, “which led him to discover a whole new character to his art,’’ Birnbaum said. In 1984, he held an exhibition at the National Museum in Stockholm called “On the Other Hand,’’ exhibiting his left-handed art works.

Mr. Reutersward leaves his wife, Tonie Lewenhaupt, a fashion journalist and writer, and five children from previous marriages.

Funeral arrangements were not immediately known.