WASHINGTON, June 20 (Xinhua) -- The U.S. Department of Justice (DOJ) on Monday afternoon released a full transcript of a 911 call made by Orlando nightclub gunman Omar Mateen under intense criticism from Republicans for previously deleting references to the Islamic State (IS) and its leader.

According to the new full transcript, Mateen told the 911 dispatcher in the 2:35 a.m. call on June 12 that he pledged "allegiance to Abu Bakr al-Baghdadi may God protect him (Arabic), on behalf on the Islamic State."

In an earlier version released by the Federal Bureau of Investigation (FBI), references to IS and its leader were withheld,  causing House Speaker Paul Ryan to quickly criticize the DOJ's decision as "preposterous."

"We know the shooter was a radical Islamist extremist inspired by ISIS. We also know he intentionally targeted the LGBT community, " said Ryan in a statement, referring to another acronym of the extremist group.

"The administration should release the full, unredacted transcript so the public is clear-eyed about who did this, and why, " said Ryan.

In explaining its decision to reverse course and release the full transcript, the DOJ admitted Monday afternoon in a joint statement with FBI that the release of uncensored transcript came after "unnecessary distraction" caused by GOP complaints.

"Unfortunately, the unreleased portions of the transcript that named the terrorist organizations and leaders have caused an unnecessary distraction from the hard work that the FBI and our law enforcement partners have been doing to investigate this heinous crime," said the statement.

"As much of this information had been previously reported, we have re-issued the complete transcript to include these references in order to provide the highest level of transparency possible under the circumstances," the statement concluded.

In addition to the transcript, the FBI also released on Monday summaries of three calls between Mateen and negotiators at 2:48 a. m., 3:03 a.m. and 3:24 a.m. on June 12.

It was revealed in the summaries that Mateen called himself an Islamic soldier and claimed that he had equipped himself with explosives.

Later investigation found no explosives.

Forty-nine people were killed and 53 others wounded, including a police officer in the June 12 shooting at a popular gay nightclub Pulse in Orlando, Florida. It was the deadliest terror attack in U.S. history since the 9/11 terror attacks in 2001.