AMMAN: The Islamic State is likely behind a double car bomb attack on the Kurdish-majority city of Qamishli that killed dozens of people early Wednesday, as local residents say they fear the bombings portend a deadly new paradigm “in response to Kurdish military advances in the region.”

A large livestock truck packed with explosives pulled onto a crowded commercial street in a western district of Qamishli, which sits on the Syrian side of the border with Turkey.

On one side of the street was a souq, or outdoor market, densely crowded with morning shoppers. On the other stood a row of government buildings, housing an Asayish [the Kurdish-led Self-Administration police] recruitment center, the local Defense Ministry and the regional Self-Administration headquarters.

The truck exploded in the middle of the street, ripping through the adjacent buildings and blowing out apartment windows as far as one kilometer away, sources on the ground told Syria Direct on Wednesday.

Outside the Asayish recruitment center in Qamishli on Wednesday. Photo courtesy of arta.fm.

The blast caused nearby fuel tanks and electrical generators to explode. Residents living several kilometers across the Turkish border photographed a massive cloud of billowing smoke following the attack that circulated on social media in the hours following the explosions.

Just moments after the initial blast, a second vehicle—smaller than the first—detonated on the scene.

“The blast was deafening,” Qamishli resident, Mustafa Ibrahim, told Syria Direct. Ibrahim is the cousin of Syria Direct reporter Mohammad Abdulssattar Ibrahim.

“Our house is just two streets over from the blast site, and we felt a tremendous shaking,” Mustafa Ibrahim said. “The explosion blew out our windows and everything.”

At the time of publication, Qamishli hospitals reported at least 40 fatalities and more than 300 injuries, while sources confirm that the casualty estimate will certainly rise.

The aftermath of two car bomb explosions in western Qamishli. Photo courtesy of arta.fm.

“We are still looking for both survivors and victims from underneath the rubble,” Qamishli’s Asayish branch announced in a Facebook post on Wednesday.

"There are victims among the military personnel, but we don't have the exact statistics at this moment,” Araz Mistou, the spokesman for what the Self-Administration calls the Defense Entity (essentially a ministry), told Syria Direct. “The number of civilian casualties is very large."

IS’s semi-official Amaq Press praised the attack, reporting at least 100 fatalities following what it called a “martyrdom operation,” but the Islamic State has not yet claimed responsibility.

The PYD-led Self Administration rules most of Qamishli, while Syrian regime forces and their allies control a number of neighborhoods and an airport immediately south. Occasional tensions notwithstanding, the two forces do not actively contest each other.

For several months, the heavily guarded Qamishli city—the de facto capital of the Kurdish-controlled northern Syria territories known as Rojava—has experienced several months of calm.

Checkpoints in and around Qamishli are equipped with explosive-detecting equipment and daytime and nighttime cameras, to protect a city where several bombings, most claimed by the Islamic State, have killed and injured dozens of civilians in recent months.

Now, Qamishli residents say that Wednesday’s bombings could forebode future attacks.

“Citizens fear that this act of terrorism… comes in response to Kurdish military advances in the region,” said Mustafa Ibrahim. “We worry that this is retaliation…particularly for Kurdish advances on the Manbij front.”

The Qamishli Self-Administration blamed the Islamic State for the attacks in a statement on Wednesday.

“In response to their many defeats…from Kobani to the ongoing fight for Manbij…the Islamic State has resorted to terrorism to persecute the civilians of Rojava.”

Since late May, US-backed coalition airstrikes have assisted the multi-ethnic, Kurdish-led Syrian Democratic Forces in a campaign to reclaim Manbij city in Aleppo province, which fell to IS in early 2014.