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Sunni insurgent group Islamic State of Iraq and al-Sham (ISIS) declared themselves a caliphate and dropped "al-Sham" from their title, according to a statement delivered by their spokesman.

Abu Muhammad al-Adnani said other jihadi factions — even those beyond Iraq and Syria — were rendered "invalid." He urged them to pledge allegiance to the newly named "Islamic State."

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"If you forsake the State or wage war against it, you will not harm it. You will only harm yourselves,” al-Adnani said, according to the Search for International Terrorist Entities (SITE) monitoring service.

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"Al-Sham" refers to the region that includes Syria, Jordan, Lebanon and the Palestinian territories, but removing the reference to the region widens the former al-Qaeda affiliate's scope, experts said.

"After seizing control of multiple territories in Syria and Iraq, ISIS feels this is a golden opportunity to seize control of the helm of the global jihadi movement," said terrorism analyst, Laith Alkhouri.

"They are quite obviously elated with their recent successes, and it has given them the confidence that they can expand their campaign into the Arabian Peninsula, North Africa, and beyond," said Evan Kohlman, a terrorism consultant with Flashpoint Partners and an NBC counter-terrorism analyst.

The insurgents overran the Iraqi city of Mosul last month and, since then, have seized a swath of Iraqi cities and towns as they seemingly make a strategic advance toward the capital of Baghdad. They have also captured Syrian territory on the border with Iraq.

"Congratulations on this clear victory, congratulations on this great triumph ... Today the nations of kufr (unbelievers) in the west are terrified," al-Adnani said in his 34-minute speech.

The rebranding also opens doors for the "Islamic State" to garner more allies. Kohlman said regions like Libya, Egypt, and the Palestinian territories have their share of "ISIS-wannabes" who are eager to fight for the group.

"The Islamic State will bring together those who want unity," al-Adnani said in his speech. He warned supporters that they would be challenged and asked why they failed to work with other groups rather than trample them. "Whom would we consult? They never recognized the Islamic State to begin with ... Whom would we consult, and whom did we step over,” al-Adnani said.

"If you forsake the State or wage war against it, you will not harm it. You will only harm yourselves."

But Alkhouri said the terror group's effort — or demand — to unify the full scope of jihadi forces under their leadership has a history of backfiring. "Each time the group has tried to change its name in order to broaden its appeal, it has come under severe criticisms from other jihadi groups who are deeply suspicious of its motives and language," Alkhouri said.

#ISIS releases it's 5 year territorial expansion plan. I'm surprised they don't want to reclaim southern Spain #Iraq pic.twitter.com/EBEl0NDXIN — Ayman Mohyeldin (@AymanM) June 22, 2014

The group has changed its name before to broaden its appeal — in 2007, they rebranded as the "Islamic State of Iraq." And within the past year, the group became the Islamic State of Iraq and al-Sham, hoping to expand its reach past Iraq and into Syria.

Alkhouri said the latest and most comprehensive name change "is simply the next logical rung on the ladder."