Seventy-six days after Yale and Peru established a 60-day timeline for a final agreement on the title to a collection of Incan artifacts from Machu Picchu — brought to New Haven by Yale explorer Hiram Bingham III nearly a century ago — the two parties still have not concluded their negotiations.

In a Sept. 14 joint statement, officials from Yale and Peru — who said they were excited about progress made when a Peruvian delegation visited New Haven — agreed to acknowledge Peru’s title to the objects and determined that Yale would return most of the artifacts.

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But some lingering disagreements led to another extension of the negotiations, until this Friday, Yale and Peruvian officials said. Both parties said they are confident that an agreement will be reached soon, but perhaps not as early as tomorrow.

Dan Martinez, attache to the American ambassador in Peru, said lawyers from Yale visited his office in Lima last month and reported that, while negotiations were ongoing, some disputes over the artifacts persisted.

“Some issues had surfaced, but they were confident that they’d be able to resolve the issues,” he said by phone from Lima on Tuesday. Martinez declined to elaborate on what those issues were.

The delay is the latest development in a long-standing dispute between Peruvians and Yale over rightful ownership of the archaeologically significant artifacts. After years of tension and threats of litigation, Peru entered into new negotiations with Yale following the election of President Alan Garcia last year and a letter this spring from University President Richard Levin to Garcia in which Levin said he suggested that they resume negotiations.

The initial agreement stipulated that Yale would return almost all of the museum-quality pieces and research collection while keeping a small, yet-to-be determined number at Yale for study.

In September, University General Counsel Dorothy Robinson said the two parties had agreed to share over the next 99 years the rights to possess and use the research materials remaining at Yale. A co-sponsored international traveling exhibition was also planned to showcase some notable artifacts, which would subsequently be housed in a museum near Machu Picchu, for which Yale would help Peru develop plans. Robinson said on Sept. 15 that the two parties would work together to reach a formal agreement within 60 days.

University spokeswoman Helaine Klasky said delays in the negotiations were due to matters within Peru.

“The Peruvians were working out some of their own internal issues on the agreement,” she said.

Cantuarias said William Cook, of DLA Piper, a Washington, D.C., law firm, now represents Peru in the negotiations. Cook declined comment for this article.

While the September visit of Peruvian Housing Minister Hernan Garrido-Lecca and his delegation showed promise for a quick resolution of the long-standing controversy, the Peruvians’ reaction has been less encouraging, Martinez said.

“I think once he returned and announced that this had been agreed to and the terms became public knowledge, some in the local community had questions and concerns about some of those provisions,” he said.

Last week, Edgar Miranda, the mayor of Machu Picchu, told Peru’s Andina News Agency that he was eager to see the artifacts returned to the 15th-century Incan citadel.

“It makes us uncomfortable that the whole world wants the pieces now,” Miranda said. “It is unfortunate because it is our right.”

Ownership of the artifacts, currently housed in the University’s Peabody Museum, has been the subject of dispute since Bingham excavated them between 1911 and 1915.

Richard Burger, an archaeology professor who co-curated a Peabody Museum exhibition in 2003 that showcased the artifacts, said while Yale will return all of the museum-quality artifacts, it is important that some fragmented objects from the research collection be retained for further study.

“Yale and Peru recognize that it would be a wonderful opportunity to create a museum where travelers and Peruvians can see these materials on their way to Machu Picchu,” Burger said. “The larger principle is the notion that it is important for these collections to be studied.”

An earthquake that ravaged Peru in August may also have contributed to the delay in the negotiations, Burger said. Garrido-Lecca has had to focus much of his effort over the past few months on rebuilding the nation, Burger said.

“The complications could have prevented them from giving full time to the agreement,” he said.

Despite these complications, both Peruvian and Yale officials said they are confident that they will soon reach a final agreement.

“I believe things are moving along,” Levin said. “I think we’re on a good course.”

Klasky wrote in an e-mail that Yale officials on Tuesday had been “assured by the Peruvian government that things are proceeding” and that the University expects finalization of the agreement in a short time frame.

Fernando Cantuarias, legal counsel to Garrido-Lecca, agreed that the negotiations are now progressing and said a final agreement will probably be reached within the next two weeks.

That Yale has a long and storied history with the artifacts as vehicles for research — Bingham was on a Yale-sponsored expedition when he rediscovered Machu Picchu in the early 20th century — is part of the motivation for Yale’s eagerness to keep some of the objects, Burger said.

Machu Picchu, an Incan palace retreat, was abandoned for centuries following the 16th-century Spanish colonization of much of South America. It is now one of the continent’s biggest tourist attractions.