Federal prosecutors in New York say they cannot meet a judge’s demands they quickly deliver documents about thousands of immigrants who have been detained nationwide for months or years as their immigration status is reviewed.

The office of U.S. Attorney Preet Bharara (buh-RAH’-ruh) laid out the government’s position in a letter to U.S. District Judge Richard Berman that was made public Wednesday.

The letter came five days after the federal judge criticized the government.

Berman said the government’s continued refusal to produce documents requested by the American Civil Liberties Union had stymied efforts to reform a system in which thousands of immigrant detainees languish in immigration jails longer than six months.

The government said it is “not feasible” to produce 22,000 records as ordered but it can produce a reliable sample of 385 files within 15 months.