The Syrian government has collapsed. This comes after anti-government forces captured the capital, Damascus, on Sunday. Russia's state-run Tass news agency reports that Syria's ousted President Bashar al-Assad has arrived in Moscow with his family. It says they were granted asylum by the Russian government, citing a Kremlin source.

Russia's foreign ministry said in a statement on Sunday that President Bashar al-Assad had decided to step down. It also said he left Syria after calling for a peaceful transfer of power.

Opposition forces have been intensifying their offensive since late November.

They seized control of Damascus on Sunday, after they stormed the presidential palace and other government buildings. They announced on state television that they had toppled the "tyrant" al-Assad.

US President Joe Biden held a news conference on Sunday. He said: "The regime brutalized and tortured and killed literally hundreds of thousands of innocent Syrians. It's a moment of historic opportunity for the long suffering people of Syria to build a better future for their proud country. It's also a moment of risk and uncertainty. The United States will work with our partners and the stakeholders in Syria to help them seize an opportunity to manage the risk."

Assad's downfall marks the end of an era. He and his father ruled Syria for more than half a century.

Meanwhile, rebel forces said on social media that all public institutions will remain under the prime minister's jurisdiction until they are officially handed over. They ordered their members not to approach those buildings. They reportedly called for national reconciliation during a broadcast on a state-run television station.

But there are concerns about the formation of a new government. Hayat Tahrir al-Sham, the group that has led this latest uprising against the Assad government, is considered to be a terrorist organization by the United Nations and the US.

The UN special envoy for Syria said "the challenges ahead remain immense."

Observers are wondering whether a new government will be recognized by the international community.

In another development, a radio station operated by the Israeli military reported on Sunday that the Israeli military had carried out airstrikes on Damascus and other places in Syria.

The radio station cited as a reason the need to prevent the opposition forces from obtaining weapons that belonged to Assad's government.