* Iran confirmed on Sunday that its Supreme Leader Ali Khamenei was killed in U.S.-Israeli airstrikes the previous day.

* The killing of Khamenei has triggered a strong response from the Islamic Republic. As the latest escalation continues, analysts warn that the Middle East could spiral into deeper instability and chaos.

* "Widening the lens to the entire Middle East, the situation is sliding into a more dangerous and unpredictable new phase," said an analyst.

CAIRO, March 1 (Xinhua) -- Iran confirmed on Sunday that its Supreme Leader Ali Khamenei was killed in U.S.-Israeli airstrikes the previous day.

"The Supreme Leader ... lived a pious life, loved Iran, secured Iran's independence, opposed foreign domination, and worked tirelessly for our country's resilience and fortitude," the Iranian Foreign Ministry said in a statement. "He will remain a living nightmare for his killers forever."

The killing of the Iranian supreme leader has triggered a strong response from the Islamic Republic. As the latest escalation continues, analysts warn that the Middle East could spiral into deeper instability and chaos.

KHAMENEI'S DEATH

Born in 1939, Khamenei assumed the position of Iran's Supreme Leader in 1989 following the death of Ruhollah Khomeini, the founder of the Islamic Republic.

For decades, Khamenei led Iran in its confrontation with Western countries, including the United States, while the country endures prolonged U.S. sanctions.

On Saturday, after sending multiple military threats, the United States and Israel initiated large-scale attacks on Iran's military facilities and high-ranking officials.

U.S. President Donald Trump said the objective "is to defend the American people by eliminating imminent threats" from Iran, and the Israeli Defense Ministry said the country launched a "preemptive" strike against Iran "to remove threats to Israel."

The Israeli military, for its part, said in a statement that some 200 fighter jets carried out an "extensive attack" in western and central Iran, marking the largest military flyover in the history of the Israeli Air Force.

In Tehran, missiles struck areas near Khamenei's office. Following a series of conflicting statements from the Israeli, U.S., and Iranian sides, Iran's Nour News, affiliated with the country's Supreme National Security Council, announced on Sunday morning the death of the supreme leader.

"Iran's leader attained martyrdom while carrying out his duties at his office," said the Nour News report, adding that the attack also resulted in the deaths of Khamenei's daughter, son-in-law, grandchild, and one of his daughters-in-law.

Following the announcement of Khamenei's death, the Iranian cabinet declared 40 days of national mourning. Iranian mourners took to the streets across various cities on Sunday, voicing their anger and calling for retribution. 

Ali Larijani, secretary of Iran's Supreme National Security Council, vowed harsh retaliation against the United States and Israel.

"Yesterday Iran fired missiles at the United States and Israel, and they did hurt. Today we will hit them with a force that they have never experienced before," Larijani said in a post on social media.

EXTENSIVE SHOCKWAVES

The U.S.-Israeli attacks have triggered massive retaliations from Iran, with explosions or missile strikes reported in Israel as well as countries such as Bahrain, Qatar, Kuwait, Jordan, the United Arab Emirates (UAE), and Saudi Arabia.

As the conflagration entered its second day, an increasing number of casualties and damage were reported across the region.

In Iran, besides the killings of senior officials and military commanders, the death toll from Saturday's attack on a girls' elementary school in the southern province of Hormozgan has risen to 165, with dozens more injured, according to Iran's official news agency IRNA.

According to Israeli officials, multiple rounds of missile attacks launched by Iran on Israel have resulted in at least one death and several injuries.

On Sunday, U.S. Central Command said that three service members have been killed and five seriously wounded in the Iran operation.

Among the Gulf states being targeted, the UAE reported that at least three people were killed and 58 others injured during Iranian airstrikes in the country.

In Oman, two drones targeted the Port of Duqm on Sunday, about 550 km south of Muscat, injuring one worker, the Oman News Agency reported, citing a security source.

With the confirmation of Khamenei's death, Iran's regional allies, including Hezbollah and the Houthis, have expressed outrage over the attacks by the United States and Israel, vowing to continue their resistance.

Israel is also preparing for an expansion of its frontlines. The Israeli military said on Sunday it was preparing to call up 100,000 reservists to increase readiness along its borders with Syria and Lebanon, as well as in the West Bank, the Gaza Strip, and southern Israel.

PROLONGED CHAOS

Following Khamenei's killing, Iran quickly moved to address the power vacuum, announcing on Sunday the formation of a three-member transitional council to handle the state duties.

Iran's Expediency Discernment Council selected Alireza Arafi, a jurist from the country's Constitutional Council, as a member of the interim leadership council, which also includes Iranian President Masoud Pezeshkian and Judiciary Chief Gholamhossein Mohseni-Ejei.

Even so, analysts believe that Khamenei's death will likely lead to significant shifts in the regional geopolitical landscape and prolonged chaos in the region.

"Since the United States and Israel violated one of Iran's red lines by assassinating the Supreme Leader, this gives Iran a reason to escalate the conflict and broaden the scope of its targets," said Abu-Bakr Al-Desouky, an Egyptian expert on Gulf affairs and Iranian politics.

Adnan Bourji, director of the Lebanese National Center for Studies, agreed that "the war is still in its early stages, and so far there are no clear indications that it will end very soon."

Pointing at the United States and Israel, Syrian political expert Maher Ihsan said, "what they are doing is just fomenting chaos, and deepening hatred and feeling of vengeance in the region."

"This is not going to bode well for Israel and America; it's just going to drown this region into further turmoil," he added.

The outbreak of war, coupled with the death of Khamenei, "marks a fundamental rupture in the regional order," said Mohammed Zakaria Aboudahab, a professor of political science from Mohammed V University in Morocco.

"Widening the lens to the entire Middle East, the situation is sliding into a more dangerous and unpredictable new phase," he added.

(Video reporters: Dong Xiuzhu, Fahrzam Vanaki and Eran Lahav; video editors: Yu Jiaming, Liu Xiaorui and Hui Peipei)■