An ISIS leader who provided the group with the religious justification for turning "infidel" women into sex slaves was killed earlier this week in a U.S. airstrike, according to reports on jihadi websites.

Posts on ISIS forums in the "deep web" say Turki al-Binali, 32, was killed Monday.

Alex Kassirer of Flashpoint Intelligence, which tracks ISIS social media for NBC News, reports that jihadis "are posting a lot of photos of him and eulogizing him (many referring to him by his kunya (battle name), Abu Sufyan al-Sulami)."

Many of the social media posts carried an Arabic hashtag that translates into "the martyrdom of Sheikh Turki al-Binali."

Flashpoint also pointed to the local Raqqa website "Raqqa Is Being Slaughtered Silently," which is run by opponents of ISIS and the Assad regime, that stated al-Binali was killed on Monday evening after "his vehicle was targeted" on "Al-Wadi street in central Raqqa."

The Pentagon declined to comment on whether al-Binali had been killed. A senior U.S. intelligence official did not dispute the reports of al-Binali's death.

Militant Islamist fighters take part in a military parade along the streets of Syria's northern Raqqa province June 30, 2014. Reuters file

A Bahraini cleric, al-Binali offered religious opinions on a variety of issues for ISIS leadership, at one point stating in an online forum that: "There is no doubt that enslaving [women] of infidel warriors" is permitted; and "it is not permitted to kill [women] and children, but they become slaves to Muslims."

ISIS has carried out military campaigns against a variety of minority Muslim and other sects, including the Yazidi minority in Iraq, which was followed by wholesale enslavement of Yazidi women and girls.

More than 3,000 women and girls were taken captive when ISIS attacked ancestral Yazidi villages around northwestern Iraq's Sinjar Mountain in August 2014.

Al-Binali was at the time reportedly head of the ISIS Research and Fatwa Department, which released a fatwa allowing rape of infidel women around the time of the campaign against the Yazidis and their subsequent enslavement.

Senior ISIS leader Turki al-Binali. via Flashpoint

A member of a prominent Bahraini family, al-Binali moved around the Gulf region as a student. He was deported from Dubai while engaged in religious studies at the Islamic and Arabic Studies College there.

In November 2014 he had become ISIS's "chief religious advisor," and was described by ISIS as an "ideologue" and "spiritual leader." Then, with the killing of chief ISIS spokesman Abu Mohammed al Adnani in an August 2016 air strike, there was speculation he would be given an expanded media role, but Laith Alkhouri of Flashpoint says his role may actually have diminished.

After al-Binali was passed over for the spokesman role, a number of jihadists said he was "marginalized and was confined to a mere role of religious authority," said Alkhouri. "He hasn’t been featured in ISIS official propaganda in two years."

ISIS statements suggested that al-Binali's primary tasks centered on providing assistance in "the recruitment of foreign fighters."

Al-Binali's death would fit within the U.S. campaign to take out those ISIS leaders involved in the use of media, particularly social media, to recruit new members.

One of the first to be killed was 21-year-old Junaid Hussain, an influential British hacker and recruiter for ISIS. He was killed in a drone attack in August 2015. Hussain had been recruiting U.S. Muslims to carry out attacks in the U.S. He was linked to planned but never executed attacks in New Jersey and New York and the 2015 attack on a Garland, Texas exhibit of cartoons of the Prophet Muhammad in which both attackers were killed and one security officer was injured.