Clashes that shook southern Syria this week have killed hundreds of people, including civilians, and drawn in an array of both local and international players, harking back to the dynamics of the country's nearly 14-year civil war.

U.S. Secretary of State Marco Rubio described the situation as "complicated" but said it looked like a "misunderstanding".

After days of bloodshed in Syria's Druze city of Sweida, survivors emerged on Thursday to collect and bury the scores of dead found across the city. A ceasefire overnight brought an end to ferocious fighting between Druze militia and government forces sent to the city to quell clashes between Druze and Bedouin fighters.

Israel carried out heavy airstrikes in the heart of Damascus on Wednesday, hitting Syrian Defense Ministry headquarters and an area near the presidential palace.

Syrian government forces had largely pulled out of the southern province of Sweida on Thursday after days of clashes with militias linked to the Druze minority that threatened to unravel the country's post-war transition.

Straddling Lebanon, Syria, Jordan, Israel and the Israeli-occupied Golan Heights, the Druze occupy a special niche in the region's complex politics. Israel has cited protecting the Druze as a reason for attacking forces from the Islamist-led government this week.

Hundreds of Druze from Israel pushed across the border in solidarity with their Syrian cousins they feared were under attack. Many then met relatives they had never seen before.