Hundreds of civilians have been killed in Syria in the last 48 hours, marking the deadliest eruption of violence since the fall of the Assad regime in December.

The U.K.-based Syrian Observatory for Human Rights (SOHR) reports that at least 830 civilians have been killed in what it described as “the largest collective act of revenge in the coast and its mountains,” with the death toll expected to rise.

More than 1,300 people have been killed in 72 hours, according to the organization. The total includes security force members and militant deaths.

It is unclear which groups are involved in the killing of civilians, with reports of different militias converging in the area, and much remains unknown about what is unfolding in Syria. Interim Syrian President Ahmed al-Sharaa called for peace on Sunday, amid reports of executions, firing squads and bodies piled in the streets.

Clashes between Syrian government forces and fighters loyal to the deposed dictator, Bashar al-Assad, have also led to hundreds more deaths on both sides.

The violence has been concentrated in the coastal areas of Tartus and Latakia, the home of the Alawite community, a small Islamic sect to which the Assad family belongs. According to the SOHR, the vast majority of the civilian dead appear to be Alawites, which NBC News has not independently confirmed.

Secretary of State Marco Rubio blamed “radical Islamic terrorists” for the killings, and urged Syria’s leadership to hold them accountable. 

Syria’s Presidency released a statement Sunday announcing its decision to form an independent national committee to investigate the events on the Syrian coast, including “causes, circumstances, and conditions” that led to the event. The statement also promised to “identify those responsible.”

But as the nation grapples with this surge in violence, here’s what we know about what’s happening on the ground, and what it could mean for Syria’s future.

What we know

Syria’s rugged Mediterranean shore was a stronghold of the Assad family’s brutal regime, which lasted 53 years before a rebel alliance led by Hayat Tahrir al-Sham (HTS) ousted Assad three months ago in a lightning-fast offensive that swept across the nation and led HTS leader Sharaa to become the new government’s interim president.

However, Syria’s northwest coast remains a fractured battleground, with armed Assad loyalists holding on to villages and remote pockets of territory.

Sharaa’s government has deployed armed forces to the region in a bid to assert control, but fierce clashes erupted last week that have left hundreds dead.

Video footage posted on social media and verified by NBC News showed dozens of bodies piled on a blood-soaked street in Latakia. Women gathered around the bloodied corpses. One can be heard sobbing, “My dad, my brother, oh, God.”

Other verified videos showed military vehicles moving through the countryside amid explosions and gunfire, while another showed soldiers indiscriminately dropping bombs from a helicopter over Latakia’s rural areas.

The SOHR is a prominent information office dedicated to documenting human rights abuses in Syria.

The group said the vast majority of people killed in the current clashes were from the Alawite sect, and that women and children were executed by firing squad in the countryside near Tartus.

NBC News has not independently verified the death toll or methods of execution.

The Associated Press reported that revenge killings were initiated Friday by Sunni gunmen, perhaps loyal to the government, with residents saying Alawites were being killed in the streets or at the gates of their homes, and their houses looted and set on fire.

SOHR also reported that 125 government security forces and 148 militants from Assad-affiliated armed groups were among the dead.

Federico Jachetti, Syria country office director for the Norwegian Refugee Council, said in a statement on Sunday that the escalation served as “a grim reminder that the situation in the country remains fragile,” and cited reports of “summary killings, widespread displacement and thousands more left trapped in their homes.”

“Syrian families across the country are yearning for a respite after long years of uncertainty and fear,” he said, calling on all parties to protect civilians.

Who are the Alawites?

The once-ruling minority is a tight-knit Islamic sect to which the Assad family belongs. Under Assad, Alawites were appointed to key positions in the military and security forces, positioning them as the elite within Syria’s state bureaucracy and security apparatus.

The rise of HTS, a former Al Qaeda affiliate with an extremist past, raised deep concerns among the Alawite community as it took power.

Sunni dominance has inflicted deep scars on the region, and minorities like the Alawites, as well as Christians, Druze and Yazidis, all have reasons to fear the rise of extremist governance.

Sharaa had tried to quell such fears, telling CNN in December, “No one has the right to erase another group.”

But the recent surge in violence suggests a different story, and challenges Sharaa’s claim that his interim government would protect all groups and foster stability.

The U.N. High Commissioner for Human Rights, Volker Turk urged Syria’s leadership to take “swift actions to protect Syrians, including by taking all necessary measures to prevent any violations and abuses.”

What does this mean for Syria?

Unifying Syria’s diverse ethnic and religious groups has been one of the major challenges of a post-Assad Syria. A significant escalation of violence could threaten the country’s fragile stability, and at worst threaten to tip the country back into civil war should the interim government lose control of some areas.

Sharaa has actively sought to rebrand himself as a unifier willing to put down his previous extremist affiliations. For a time, this strategy appeared successful, generating a surge of goodwill and optimism.

In February, a video surfaced showing Sharaa waving from the sunroof of a black vehicle, surrounded by a jubilant crowd during his first visit to Latakia, where he appeared receive a hero’s welcome.

Internationally, the explosion of violence may derail the progress Sharaa has made in reassuring Western leaders that he can ferry in a Syria free of threats.