With a solemn ceremony in Stockholm's antiquities museum, Sweden on Saturday marked the return of 22 skulls looted from a native Hawaiian community mainly in the 17th century.

The symbolic ceremony — attended by guests from Hawaii and the Nordic countries' own indigenous Sami population — was part of Sweden's increased efforts to return indigenous remains collected by scientists across the world in the 17th and 18th centuries.

The Swedish government in 2005 ordered its museums to search through their collections, and has since returned more than 20 human remains, mainly to Australia.

The Hawaiian skulls had been returned privately earlier Saturday so that the Hawaiian delegates could perform a ritual according to traditional customs.

Museum director Lars Amreus said he hoped the return would help "fulfill the spiritual circle" of those whose graves had been violated by the Swedish scientists.

"We know that they were collected, although by today's standards: they were looted," Amreus said.

Greeting Amreus at the ceremony with the traditional nose-to-nose — or breath-of-life — greeting "Ha," Hawaiian delegation head William Aila thanked the Nordic country for helping to recover the remains of their ancestors.

"I cannot adequately express the thankfulness... for a very, very worthy endeavor, and that is to greet our ancestors and accompany them home," Aila said in a speech during the ceremony in the museum's round-walled "Gold Room."

Five of the skulls were returned by the museum itself, while 17 came from Stockholm's medical university Karolinska Institutet. They were not on display during the ceremony.

Aila said the skulls would "be reburied in the soil of their birth" back in Hawaii.

Of the 22 skulls, at least 15 had been taken from the Pacific islands by Swedish scientists in the 1880s during an expedition around the world. The museum received five of them through a donation in 1997, while it was unclear when Karolinska received its collection.

On Wednesday, Sweden will return to New Zealand a near complete skeleton, a skull and three skeleton parts all believed to have been from the indigenous Maori population. A similar ceremony involving representatives from the Museum of New Zealand, Te Papa Tongarewa, is planned.