A statue near Boathouse Row ended up in the Schuylkill overnight in what appears to be an act of vandalism.

Officials responded to a "vandalism in progress" shortly after 2 a.m. Tuesday, and found the monument of Thorfinn Karlsefni, a Viking explorer, yanked off his pedestal and submerged in the river, authorities said. Philadelphia police said six to seven juveniles are suspected of using ropes to pull the statue down, though no arrests have been made.

The tribute to the "Icelandic hero" is made of bronze and stands at 7 feet 4 inches tall upon a granite base along the Schuylkill River Trail, according to the Association for Public Art. It was installed in 1920 and was "the first of a series of sculptures on Kelly Drive."

In its description of the statue, the art association noted that "little is known" of Karlsefni, but sculptor Einar Jónsson "captured the Viking spirit, conveying how Thorfinn might have appeared since no known images exist."

Margot Berg, public art director for the city, said a crane was being used to hoist a piece of the pedestal upright and then remove the rest of the statue from the Schuylkill.

"We are working with the police marine unit divers to get the statue strapped and then a rigger will lift it out and we'll take it to a conservator's studio to assess the damage," Berg said in an email. "We won't know how long the restoration will take until we get it out."

Last October, the statue was spray-painted with "anti-Nazi language," 6ABC reported at the time.

The statue has been a meeting place for white nationalist gatherings in the past.

Neo-Nazis gathered there for a Leif Erikson Day rally organized by Keystone United in October 2013, while a group of about 75 supremacists came together to lay a wreath at Karlsefni's statue in October 2008.

"We feel it is our duty to study our past and never forget the extreme obstacles that our European ancestors fought and died for," Keystone United member Joseph Phy told the Inquirer and Daily News at the 2013 event. "Leif Erikson was a great Norse explorer. His historic voyages led him to be the first European to set foot on North American soil. We can look back on our European ancestors, relearn from them and overcome the great challenges that we face today."

Police are continuing to investigate.