DAMASCUS, March 23 (Xinhua) -- The U.S.-backed Syrian Democratic Forces (SDF) announced on Saturday the defeat of Islamic State (IS), but analysts warn that the threats of terrorism and war in Syria are not over yet.

SDF spokesman Mustafa Bali made the declaration after capturing the town of Baghouz, the last IS redoubt in eastern Syria, signalling the demise of the militant group's self-declared caliphate.

Bali also sent congratulations to the world on the elimination of the IS rule that once spanned a third of Iraq and Syria.

Despite the euphoria, analysts in Damascus warn that the physical defeat of IS doesn't mean the defeat of its ideology, which attracted thousands of fighters from around the world to join its quest to conquer Syria and Iraq.

Maher Ihsan, a political expert, told Xinhua that most of the radical groups start with radical ideas that are later translated into actions.

"The ideas start to spread among people and the people form a group that has a presence in a certain area and thus the physical presence of Daesh has ended, but their thoughts and methodology are not yet defeated," he said, using the Arabic acronym of IS.

Muhammad al-Ashqar, a Syrian journalist and political expert, cautioned that there will be quite sometime before the IS is completely defeated as it still has sympathizers in Syria and elsewhere around the world, because its radical ideas are still alive.

"The defeat of the radical methodology requires education and true interpretation of the true teachings of any religion, and thus the physical entity of IS may be gone for now, but it could return at any given time or place," he added.

SDF VS. SYRIAN ARMY

Analysts also say that the possibility of a war between the Kurdish forces and Syrian Army cannot be underestimated.

Ihsan noted that the party which declared the victory is the SDF, which is backed by the U.S. and expected to gain benefits from this achievement at least in the near future.

But the SDF will soon have to deal with the Syrian government, which recently said that the Kurdish-led groups such as the SDF and its allied forces in northeastern Syria will face two choices: either to reconcile with the government or face the Syrian Army which will take back the areas.

Ihsan said that Syrian Defense Minister Abdullah Ayyoub recently issued a threat to the Kurdish-led forces by urging them to choose reconciliation or war.

The Syrian government is showing unwavering determination to retake the entire country back, as reflected in the recent visits of Syria's allies to Damascus.

On March 18, the military commanders of Syria, Iran and Iraq discussed in Damascus anti-terror coordination, opening borders, and restoring all Syrian areas.

The meeting was attended by Ayyoub as well as Othman al-Ghanmi, chief of staff of the Iraqi military, and Mohammad Bagheri, chief of staff of the Iranian Armed Forces.

Ayyoub vowed that the Syrian state will completely wrest control over all of Syria sooner or later, noting that there will be no inch of Syria should be left out of the government control.

"The only card in the hands of the U.S. and its allies is the SDF and it would be dealt with in accordance with the two ways adopted by the Syrian state: either through reconciliation or liberating the areas that they control by force," he said.

He also mentioned Idlib, the last major rebel stronghold in Syria, saying the province will return to the government control sooner or later.

The Syrian government has for long said that it would retake Idlib from the ultra-radical rebels. However, a planned military campaign was put on hold late last year when Russia, Iran, and Turkey agreed to create a demilitarized zone in Idlib.

FATE OF IS LEADER AND FOREIGN FIGHTERS

Meanwhile, IS leader Abu Bakr al-Baghdadi has not been declared captured or killed.

First founded in Iraq amid the U.S.-led invasion of the country in 2003, IS emerged in Syria after the civil war began there in 2011.

Al-Baghdadi broke ties with the terror group al-Qaida and renamed his group as "the Islamic State of Iraq and the Levant" in 2013.

The IS leader caught world attention in July 2014, by declaring the creation of a caliphate while standing at the pulpit of the Great Mosque of al-Nuri in Mosul, Iraq.

So far, al-Baghdadi's fate remained unknown despite the rumors that he was already killed in airstrikes in Syria.

Moreover, the fate of IS foreign fighters and their families detained in Syria also remain unresolved.

Currently, thousands of IS militants and their family members are in the custody of the SDF at the al-Hol camp in the countryside of the northeastern province of Hasakah.

Many of them are from Europe and elsewhere, but their original countries reject their return fearing about national security. France and the United Kingdom have stripped some of the fighters of citizenship to prevent them from coming back.