Though Golani, in his first video appearance, said the new group will have "no affiliation to any external entity," U.S. officials quickly dismissed the rebranding as a public relations ploy.
The supposed breakup comes less than two weeks after Secretary of State John Kerry said the United States and Russia had agreed to cooperate in Syria against al Nusra
in an effort to "restore the cessation of hostilities, significantly reduce the violence and help create the space for a genuine and credible political transition" in the war-ravaged country.
Al Qaeda has given the split its blessing, according to veteran Egyptian operative Ahmad Hasan Abu al Khayr al-Masri, who has been elevated to the No. 2 leadership position in the terror group. Masri spoke in an audio message released Thursday by al Nusra.
The man Masri would replace, al Qaeda leader Ayman al-Zawahiri, in a separate message also expressed support for the decoupling and called for infighting between jihadist groups to end.
Golani said the change does not represent an ideological split. Instead, it was intended to remove the excuse used by the international community -- led by the United States and Russia -- to "bombard and displace Muslims ... under the pretense of targeting Jabhat al Nusra."
The group emerged in late 2011 during the early days of the Syrian civil war and was initially largely made up of battle-hardened Syrians who had traveled to Iraq to fight U.S. troops during the American engagement there.
It has become one of the most effective factions fighting the Syrian regime and currently controls swaths of northwestern Syria.
In 2012, the State Department added al Nusra Front
to the list of aliases for al Qaeda in Iraq, which had already been designated a foreign terrorist organization.
The name change does not alter Washington's perception of the group, according to the State Department.
"We judge any organization, including this one, much more by its actions, its ideology, its goals," State Department spokesman John Kirby said of al Nusra.
"We judge a group by what they do, not by what they call themselves. ... Thus far, there's no change to our views about this particular group. We certainly see no reasons to believe that their actions or their objectives are any different. And they are still considered a foreign terrorist organization."
Speaking at the Aspen Security Forum on Thursday, Director of National Intelligence James Clapper called the rebranding a "PR move ... to create the image of being more moderate in an attempt to unify and galvanize and appeal to other opposition groups in Syria."
Clapper also said al Nusra is concerned about being targeted by Russia.
U.S. Army Gen. Joseph Votel, commander of U.S. Central Command, told the Aspen Security Forum that al Nusra's new branch "comes back into the core ideology and core approach at the center. ... It's still al Qaeda."
Experts said the split will enable al Nusra to more deeply ally itself with other rebel groups in Syria. It also fits into Zawahiri's longstanding strategies of gaining mass Muslim backing for al Qaeda and push for jihadists to build a base for future expansion in the Arab world.
Al Qaeda's new No. 2 man, Masri, had been under some form of detention in Iran but was released in March 2015 in a reported prisoner swap. Western intelligence agencies believe he may be in Syria.
The distribution of his audio message by the Syrian jihadist group -- in addition to Masri's reference to studying the Syrian arena -- further points to his presence in Syria.
According to a 2005 designation by the U.S. Treasury Department, Masri's real name is Abdullah Muhammad Rajab Abd al-Rahman. He was born in northern Egypt in 1957.
A former al Qaeda insider, who met the Egyptian operative in Afghanistan, described al Masri as responsible for travel logistics and expense claims for operatives sent on international missions before 9/11.
Masri, the insider said, has been close to Zawahiri and was part of his Egyptian Islamic Jihad group since the late 1980s, according to the former al Qaeda operative.
Masri traveled to Sudan with Zawahiri in the early 1990s and later to Afghanistan, where he joined Osama bin Laden's entourage. The circumstances of his capture by Iran are unclear.
Al Qaeda operative Sulayman Abu Ghayth told U.S. investigators that he, Masri and other al Qaeda operatives were arrested in Shiraz, Iran, in April 2003 and jailed in Tehran for nearly two years.
Ghayth said they were transferred to apartment-like housing "without windows" and then to small houses inside a military compound in the Tehran area, where they were joined by members of bin Laden's family, including Hamza bin Laden, according to U.S. court documents.
The former al Qaeda insider described Masri as an officious bookkeeper with little charisma who was often mocked by other jihadists.
In January, a report by the Institute for the Study of War and American Enterprise Institute said al Nusra was a greater threat to the United States
in the long term than ISIS, making the United States' focus on the latter group misguided.