The University of Illinois on Tuesday refused to release records relating to Barack Obama's service to a nonprofit group linked to former 1960s radical activist William Ayers.
The university's Chicago campus said the donor of the records that document the work of the Chicago Annenberg Challenge has not yet turned over ownership rights to the material.
The university is "aggressively pursuing" an agreement with the donor, and as soon as an agreement is finalized, the collection will be made accessible to the public, the university said in a one-paragraph statement.
There was no indication when an agreement will be worked out. The university did not identify the donor who it said was concerned that the release not invade personal privacy.
The Obama campaign said the senator does not have control over these records or the ability to release them, adding that it has made many documents related to Obama's life available to the public and that "we are pleased the university is pursuing an agreement that would make these records publicly available."
On Monday, the National Review magazine posted an online article saying that the institution had initially declared that the records were open to inspection, but that the university subsequently reversed its position.
On Tuesday, the university said that there had been a misunderstanding about the status of the collection.
During a primary debate in Philadelphia last October, Obama criticized rival Hillary Rodham Clinton over the release of presidential papers from the National Archives. Clinton said at the time that neither she nor husband Bill Clinton could do anything to speed the process of review at the Archives before papers from the Clinton era could become public.
Obama compared her record of public disclosure of records to that of the Bush administration, saying the country had "just gone through one of the most secretive administrations in our history."
In March, edited versions of the former first lady's appointment calendars were publicly released.
