The Islamic Movement of Uzbekistan (IMU) is not only allied to the Islamic State (IS) group, it now considers itself part of it.
In a 2-1/2 minute video viewed by RFE/RL on August 6, IMU leader Usmon Ghazi and his fighters are shown taking an oath of allegiance, in Arabic, to IS and its leader Abu Bakr al-Baghdadi.
The confirmation of subservience, coming directly from Ghazi, would be significant in and of itself. But the leader of the extremist group active in Pakistan and Afghanistan does not stop there.
Ghazi goes on to say, according to a narrator's translation of his oath, that "from now on we are not just a movement, we are a state." IMU fighters, he says, should henceforth be described as IS fighters from the Khorasan region.
"Thank the Lord, following the Almighty's will we have pledged our allegiance (Bayaht, or Bay'a) to the Caliphate that has bowed to Islam," Ghazi is quoted as saying. "And we are now part of it."
The declaration is significant because it is the latest, and perhaps final, step of the IMU's journey to full absorption into the IS, which seeks to establish a vast caliphate centered on the Middle East and extending into Asia.
In September 2014, Ghazi issued a statement on the IMU's website in which he said that "on behalf of members of our Islamic Movement, I herewith announce to the world that we are siding with the Islamic Caliphate."
But as Damon Mehl of the of the Combating Terrorism Center at West Point noted in a June analysis, Ghazi fell short of using the word Bay'a, which would indicate a pledge of allegiance.
Such a pledge came in March, as reported by RFE/RL's Uzbek Service, but from a person named Sadulla Urgenji who claimed to be from a group of Uzbeks fighting for IMU in northern Afghanistan.
Urgenji said his group was recognizing the authority of IS leader Baghdadi, but the message did not come from Ghazi himself.
The latest message from the IMU leader leaves no uncertainty.
"We now say that we have our state and there are possibilities for all for hijrat (holy migration)," Ghazi explains in the new video. "Those who want to join us, let them join."
The video does not state when it was filmed, but it appears to show scenes from Afghanistan and describes itself as representing the Khorasan Vilayat, or Khorasan region.
In January, an Islamic State spokesman announced the group's expansion into Khorasan -- an ancient province that included parts of modern Iran, Afghanistan, Tajikistan, Turkmenistan, and Uzbekistan.
The video's emergence comes shortly after the IMU issued a statement in which outlined its grievances with the Afghan Taliban, with which it has had longstanding relations.
In the August 2 statement obtained by RFE/RL's Uzbek Service, the IMU accused the Taliban of lying about the death of Mullah Mohammad Omar, and demanded that it tell the truth about the late Taliban leader's demise.
Afghan officials announced on July 29 that Omar died in 2013 in Pakistan, and the Taliban confirmed the news shortly thereafter, although without naming a time or place.
The IMU statement declared that the Taliban "cannot be trusted," and accused the Afghan militant group of collaboration with Pakistan's spy agency, the Directorate for Inter-Services Intelligence (ISI).
The IMU mainly consists of men and women from Uzbekistan and other former Soviet Central Asian republics. Aside from its relations with the Taliban, it was also known to have ties to Al-Qaeda
It is on the U.S. State Department's list of foreign terrorist organizations and is banned in Central Asian countries and Russia.