Senior Republican lawmakers on Tuesday called on the Obama administration to reverse an "unprecedented" decision to hide the details of a refugee transfer agreement by classifying the information.

"[C]lassification of an agreement regarding individuals to be considered for admission by the U.S. Refugee Admissions Program is unprecedented," Senate Judiciary Committee Chairman Chuck Grassley, R-Iowa, and House Judiciary Committee Chairman Bob Goodlatte, R-Va., wrote in a letter to the State Department and the Department of Homeland Security.

The letter pertains to a deal struck by Secretary of State John Kerry and the Australian government, by which the United States will accept 2,400 refugees who were denied entry into the Australia. The migrants are currently being held outside Australia in offshore detention centers, which have been a source of international embarrassment and domestic political infighting for the Australian government.

"We appreciate your making staff available to provide us with the document in a classified setting and to brief us regarding the circumstances surrounding the agreement," the lawmakers wrote to Kerry and Homeland Security Secretary Jeh Johnson in their Dec. 6 letter. "It is now absolutely apparent to us that there was no reason for the agreement to be classified from the outset, and that it should not continue to be classified. To that end, we request that you declassify the document outlining the agreement so that the American people can read it."

The terms of the deal could be politically delicate on both sides of the Pacific. Kerry announced the agreement in November, two months after Australian Prime Minister Malcolm Turnbull agreed to accept Central American migrants from Costa Rica who might otherwise have sought refuge in the United States. Turnbull's willingness to do so raised speculation that he had cut a deal with the Obama administration, but the Australian government denied that.

"There is not, and there will be no people swap," a member of Turnbull's administration said in September.

Goodlatte and Grassley argued that "the security implications" of accepting refugees mandates greater transparency.

"These migrants are nationals of countries like Somalia, Syria, Pakistan, Iran, and Sudan, as well as others," the lawmakers wrote to Kerry and Johnson. "The American people have a right to be fully aware of the actions of their government regarding foreign nationals who may be admitted to the United States. American taxpayers not only foot the bill for the majority of the refugee resettlement in the United States, but they bear any consequences regarding the security implications of those admitted to the U.S."