CLEVELAND, Ohio - The Cleveland Museum of Art announced early Monday that it voluntarily returned to Cambodia a much-beloved 10th-century statue of Hanuman, the Hindu monkey god, after uncovering evidence that it was probably looted during the country's bloody civil war.

The Cambodia Daily newspaper published photos on its website early Monday morning U.S. time showing what it described as the arrival and partial uncrating of the Hanuman at Phnom Penh International Airport.

Xinhua, the Chinese news agency, reported that Cambodian officials held a Buddhist ceremony at the airport to welcome the arrival of the 800-pound sandstone sculpture, which stands roughly 3.5 feet high and depicts a kneeling human figure with the head of a monkey.

A favorite with generations of schoolchildren who imitated its distinctive, kneeling pose during tours with docents, the sculpture has been on nearly constant display at the museum since the museum acquired it in 1982. The work was still illustrated on the museum's website early Monday.

The Cleveland museum said it uncovered evidence late last year that the work's head and body were offered for sale separately in Bangkok, Thailand, in 1968 and 1972, respectively, during the Vietnam War and the Cambodian civil war.

The Cleveland museum also learned in February, in talks that it initiated with Cambodian officials in Phnom Penh, that a government excavation showed the sculpture's base matched a pedestal at the east gate of the Prasat Chen Temple, part of the Koh Ker archaeological site.

The excavation at the site, roughly 15 miles from the border of Thailand, uncovered fragments that match details on the Cleveland Hanuman, including the earring missing from the right side of its head, museum officials said.

Museum director William Griswold, who arrived in Phnom Penh Sunday, is scheduled to sign documents Tuesday along with officials including the country's deputy prime minister, the museum said.

The museum said it also entered an agreement with the National Museum of Cambodia to facilitate joint projects, with specifics to be hammered out in coming months.

The talks with Cambodian officials were "enormously cordial, and generous and forthcoming," Griswold said in an interview before his departure.

"I'm very optimistic that the conversations we have begun will result in cooperation of various kinds, and we are continuing to explore those possibilities," he said.

Referring to the sale of the Hanuman head and body in Bangkok in 1968 and 1972, Griswold said that "we have no proof that the piece was removed from the [Prasat Chen] site at that time."

But he added: "Our research revealed a very real likelihood that it was removed from a site enormously important to the kingdom of Cambodia during a terrible time and its return was completely consistent with the highest legal and fiduciary standards."

The restitution of the Hanuman is part of a rising trend in which "source countries" rich in antiquities are pressing for the return of allegedly looted objects, sometimes based on hard evidence, sometimes not.

Cleveland's Hanuman is the sixth of the so-called "blood antiquities" returned to Cambodia by American institutions in recent years, including two from the Metropolitan Museum of Art in New York, one from the Sotheby's auction house, one from Christie's auction house and one from the Norton Simon Museum in Los Angeles.

The restitution also follows the Cleveland Museum of Art's decision in 2009 to hand over 14 works of art to Italy.

Italian authorities said that evidence from a 1995 police raid in Geneva, Switzerland, showed that 13 of the objects were looted from sites in Puglia and laundered through a smuggling operation. The 14th item was a Renaissance-era crucifix stolen from a church near Siena.

The Cleveland museum also faced pressure from Greece in 2007, without hard evidence, to return an ancient bronze statue of Apollo attributed to Praxiteles.

In 2012, Turkey pressed the museum to return 22 objects that it said were looted and illegally exported. When queried by The Plain Dealer, Turkish authorities did not provide any proof of looting and smuggling.

Unnamed Cambodian officials were quoted by The New York Times in 2013 as saying that the Hanuman had been looted from Prasat Chen and that the country wanted it returned.

A year later, the museum reported that Sonya Quintanilla, its curator of Indian and Southeast Asian art, had traveled to Prasat Chen with a mold of the base of the Hanuman. She found that it did not match any excavated pedestals there, and concluded at the time that it had not been looted.

Her investigation, conducted with permission from the Cambodian government, focused on excavated portions of the west gate at the site, Griswold said.

At the time, Cambodian authorities had not excavated the east gate, where government archaeologists later found the matching pedestal and the missing earring, Griswold said.

The museum said it bought the Hanuman in 1982 from New York art dealer Robert H. Ellsworth, who died in 2014 at age 85.

Ellsworth, in turn, acquired the work from the estate of New York financier and collector Christian Humann, whose Pan-Asian Collection was widely exhibited.

The Hanuman was published in a 1977 catalog for the "Sensuous Immortals" exhibition, which traveled to four American museums.

After Quintanilla's 2014 trip to Cambodia, she continued to research the sculpture's provenance, or ownership history, Griswold said.

Her research showed that the work's head was offered for sale in 1968 in Bangkok, followed by the body in 1972. Griswold said that the pieces were in the possessed at the time by Douglas Latchford, a British art dealer. (The museum later specified that it did not have documentary evidence that Latchford sold the pieces).

U.S. federal authorities in 2012 accused Latchford of having knowingly purchased a looted 10th-century Khmer sculpture that was later returned to Cambodia by Sotheby's. Latchford denied having owned the work, according to news reports.

Griswold said that Cambodian officials never officially contacted the Cleveland museum to discuss the Hanuman.

Instead, he said, the museum acted on its own to discover as much of the work's true history as it could. He said Cambodian officials have also acknowledged that that the museum acted in good faith in its 1982 purchase of the Hanuman.

"I'm proud that we have been proactive," Griswold said.

Griswold said a factor in the museum's decision to return the Hanuman was that the body was offered for sale in Bangkok in 1972, two years after the 1970 UNESCO Convention aimed at halting the looting and trafficking of antiquities.

But the Hanuman story is not an indication that the museum would return other antiquities whose "find sites" are known, including a large Mayan stele, or sculpted panel, known to have been removed from a site in Guatemala and purchased by the museum in 1967.

"Each situation is going to be completely different, and the analysis is going to be different for each one," Griswold said.

This story was updated to reflect the museum's clarification that it does not have documentary evidence of the sale of the Hanuman head and body in 1968 and 1972 in Bangkok, respectively, but that it knows the pieces were offered for sale there during those years.