FBI Director Christopher Wray said the bureau will cooperate with a House Judiciary Committee subpoena for documents on how it handled the Hillary Clinton email investigation.

But Mr. Wray said in a statement issued late Tuesday the bureau will need more time to produce the “thousands” of documents. To speed up the process, Mr. Wray has doubled the number of workers reviewing the records to 54 from 27 and has authorized two shifts per day from 8:00 am to 12:00 am.

“I agree the current pace of production is too slow,” Mr. Wray said.

Rep. Bob Goodlatte, Virginia Republican, issued the summons last week. He, along with Rep Trey Gowdy, House Oversight Committee chairman and South Carolina Republican, are probing whether political bias influenced how the FBI handled the investigation into Mrs. Clinton’s use of a private email server. President Trump and his allies have alleged Obama-era holdovers in the FBI have covered for Mrs. Clinton.

Mr. Goodlatte criticized the Justice Department’s response to his requests for documents. He said in a March 18 interview on Fox News that he and other members of the House “are very concerned about the slow nature of those documents being produced.”

Assistant Attorney General Stephen Boyd said Tuesday in a letter to Mr. Goodlatte that the Justice Department is cooperating, but the sheer volume of documents and number of redactions have slowed down production.

For example, Mr. Boyd said the FBI has more than 1,000 pages dealing with Russia’s influence on the 2016 election, which he described as “highly sensitive.”

Mr. Boyd also noted that the Committee had requested documents related to the firing of former FBI Deputy Director Andrew McCabe. Such documents are difficult to produce, Mr. Boyd said, because Mr. McCabe had only been fired less than a week before the subpoena.

FBI officials will reach out to the members of the House Committee to discuss fulfilling the subpoena’s demands, Mr. Boyd said.

“We take the committee’s request for information seriously and seek to accommodate all requests for information,” Mr. Boyd wrote.