A feud between allies of Russian President Vladimir Putin spilled out into the open after the head of the Russian Investigative Committee, Alexander Bastrykin, called for officials to "urgently" impose a ban on wearing niqabs in the country.

Bastrykin, commenting on the June 23 attacks by Islamic militants in Russia's southern Republic of Dagestan, said on Saturday that the perpetrators were "Islamist terrorists" who were "able to carry their banner of Islamic terror" into the country.

The attack, which saw militants attack Christian and Jewish places of worship, left 21 people dead.

Bastrykin called for Russia to respond by adopting a ban on the wearing of the niqab, a long garment worn by some Muslim women that leaves only the area around the wearer's eyes exposed.

He said it is the duty of the State Duma to pass a law prohibiting the niqab.

[In Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan] it's banned, but here it's allowed. Why? I don't know, I'm not a legislator but…we urgently need to ban it," Bastrykin said, responding to a suggestion from an audience member at the International Youth Legal Forum in St. Petersburg.

His remarks prompted criticism from Chechen leader Ramzan Kadyrov, who is the head of the predominantly Muslim southern Russian republic of Chechnya, and a close ally of Russian President Vladimir Putin.

Kadyrov has ruled the republic of Chechnya since 2007. His Chechen fighters have fought alongside Putin's troops in the full-scale invasion of Ukraine. On November 27, 2023, Kadyrov said a further 3,000 of his fighters were ready to fight in Ukraine as part of new units of the Russian Defense Ministry and the Russian National Guard.

"Bastrykin recalled the recent terrorist attacks in Rostov and Dagestan, and called their perpetrators 'Islamist terrorists,'" Kadyrov wrote on his Telegram channel, warning Bastrykin to be "extremely careful" with such statements.

"I have said many times and I emphasize once again that Muslims have not committed and do not commit terrorist acts," Kadyrov wrote. "At the same time, I very much hope that Bastrykin will not compare Islam with terrorism in the future."

Newsweek has contacted Russia's Foreign Ministry for comment via email.

The Institute for the Study of War (ISW), a U.S.-based think tank, said in its analysis of the conflict in Ukraine on June 29 that "two prominent Russian officials appear to be spearheading divergent paths for addressing religious extremism in Russia" as ethnic and religious tension in Russia continues to rise.

"Russian milbloggers and lower-level Russian officials have previously participated in similar debates, and it is significant that Kadyrov was willing to openly criticize another high-level Kremlin official on this issue," the ISW said.

Bastrykin has previously positioned himself as a prominent figure in Russia's ultranationalist movement and "is placing himself at odds with Kadyrov, who often presents himself as a representative of Russia's Muslim minority."

In its June 30 update, the think tank noted that the head of the Russian republic of Dagestan, Sergei Melikov, has since publicly sided with Kadyrov over the matter.

The ISW has assessed that Putin "may weigh in on Kadyrov's and Bastrykin's debate in hopes of quelling concerns among Russians about potential Islamist terrorist threats and stopping a potential conflict between Bastrykin and Kadyrov before it expands to other senior Russian officials."

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