The Syrian government of Bashar al-Assad fell on Sunday after armed rebel forces entered the capital city of Damascus, bringing an end to the al-Assad family’s 50-year rule in the country, reported AP.

Opposition groups claimed that Assad had fled the capital and that his whereabouts were unknown.

Syrian state television broadcast a video in which a group of men declared that “tyrant al-Assad has been toppled” and that all prisoners have been freed from the prisons of Damascus, reported Al Jazeera. Opposition groups urged their combatants and citizens to protect Syria’s public infrastructure.

Assad ruled Syria for nearly 25 years, beginning in July 2000 after the death of his father Hafez al-Assad, who had been the country’s president since 1971.

Syrian Prime Minister Mohammed Ghazi al-Jalali said in a video statement that the government was willing to “extend its hand” to opposition groups and transfer its functions to a transitional government.

Jalali also called for free and fair elections to allow the Syrian people to choose the next elected government.

“I am in my house and I have not left, and this is because of my belonging to this country,” Jalali said. He said he would go to his office to continue work in the morning and called on Syrian citizens not to deface public property.

Abu Mohamed al-Julani, leader of the opposition group Hayat Tahrir al-Sham, instructed combatants not to attack public institutions or services, reported Al Jazeera.

The Qatar-based news service reported that opposition fighters had entered the presidential palace in Damascus, while a large crowd gathered in the city’s main square chanting slogans of freedom to celebrate the end of the Assad family’s rule.

The Syrian army informed its officers on Sunday that Assad’s regime had ended, reported Reuters, citing an unidentified official. The army later claimed it was conducting operations against “terrorist groups” in Hama, Homs and Deraa countryside.

The collapse of the Assad regime is seen as a blow to Russia and Iran, which backed the dictator through more than 13 years of unrest in the country.

The Iranian embassy in Damascus was attacked on Sunday, BBC reported citing Iranian media.

United Nations special envoy to Syria, Geir O Pedersen, described Sunday’s developments as a “watershed moment” in Syria’s history. He said that the last 13 years of conflict had caused “relentless suffering and unspeakable loss”.

Pederson added: “This dark chapter has left deep scars, but today we look forward with cautious hope to the opening of a new one - one of peace, reconciliation, dignity and inclusion for all Syrians.”

The United States Deputy Assistant Secretary of Defence Daniel Shapiro said that “no one should shed tears” over the fall of the Assad government and urged all parties in Syria to protect civilians and work towards an inclusive political settlement, reported Al Jazeera.

Shapiro also confirmed that US forces would remain in eastern Syria to counter the Islamic State and that their presence would be unrelated to other aspects of the Syrian conflict.

More than 3.5 lakh persons have been killed in the civil war that started in Syria in March 2011, according to the United Nations. Over 6 million Syrians have fled the country and 6.7 million have been internally displaced. More than 14 million persons in Syria are in need of humanitarian aid.

A coalition of opposition forces mounted a surprise offensive against the Bashar al-Assad government in the past week. The latest round of fighting has led to at least 3.7 lakh persons getting displaced since November 27, according to the United Nations.

Some of the opposition groups have been designated as terrorist organisations by the United Nations, United States, the United Kingdom, Russia and the European Union.