A car bomb exploded Saturday in a northern Syrian town controlled by Turkey-backed opposition fighters, killing at least 12 people and wounding several others, Syrian opposition activists and Turkey's Defence Ministry said.

Northern Syria has been hit by several explosions that have killed and wounded scores of people over the past month. That's since Turkey began a military operation against Kurdish fighters in the wake of Donald Trump's decision to pull the bulk of American troops out of northern Syria.

The UK-based Syrian Observatory for Human Rights reported that 14 people, including nine civilians, were killed Saturday the town of al-Bab in Aleppo province. The Aleppo Media Centre, an activist collective, said 12 people were killed in the blast in a busy part of town near a bus station.

Turkey's Defence Ministry said the blast killed 18 people and blamed the main Kurdish militia, known as the People's Protection Units.

It is not uncommon for reports to give differing casualty figures in the immediate aftermath of this kind of attack.

Turkey launches offensive into Syria Show all 25 1 /25 Turkey launches offensive into Syria Turkey launches offensive into Syria Turkish soldiers with armored vehicles EPA Turkey launches offensive into Syria A woman flees with her children during Turkish bombardment on Syria's northeastern town of Ras al-Ain AFP/Getty Turkey launches offensive into Syria Smoke billows following Turkish bombardment on Syria's northeastern town of Ras al-Ain in the Hasakeh province along the Turkish border on October 9, 2019. - Turkey launched an assault on Kurdish forces in northern Syria with air strikes and explosions reported along the border. President Recep Tayyip Erdogan announced the start of the attack on Twitter, labelling it "Operation Peace Spring". (Photo by Delil SOULEIMAN / AFP) (Photo by DELIL SOULEIMAN/AFP via Getty Images) DELIL SOULEIMAN AFP/Getty Turkey launches offensive into Syria The first group of Turkish infantry prepare to enter Syria on the border Getty Turkey launches offensive into Syria Civilians flee AFP/Getty Turkey launches offensive into Syria Smoke billows from targets inside Syria AP Turkey launches offensive into Syria Turkish armoured vehicles enter Syria in Akcakale Getty Turkey launches offensive into Syria Civilians leave as smoke rises from Ras al-Ain AFP Turkey launches offensive into Syria A multi-rocket launcher fires in an unknown location Turkish Defence Ministry via Reuters Turkey launches offensive into Syria People wave as Turkish soldiers prepare to cross the border Getty Turkey launches offensive into Syria Girls stand together in Ras al Ain town Reuters Turkey launches offensive into Syria A woman walks as smoke billows following Turkish bombardment in Syria's northeastern town of Ras al-Ain AFP/Getty Turkey launches offensive into Syria A Turkish army's tank drives down from a truck towards the border with Syria AFP/Getty Turkey launches offensive into Syria Turkish jet taxis on tarmac after returning to a military base in southeast Diyarbakir Reuters Turkey launches offensive into Syria A Turkish armored vehicle drives down a road during a military operation in Kurdish areas of northern Syria EPA Turkey launches offensive into Syria People sit on belongings at a back of a truck as they flee Ras al Ain town Reuters Turkey launches offensive into Syria Turkey-backed Syrian opposition fighters enter Tel Abyad AFP/Getty Turkey launches offensive into Syria Civilians flee AFP/Getty Turkey launches offensive into Syria People flee Tal Abyad North Press Agency/Reuters TV Turkey launches offensive into Syria People wave as Turkish soldiers prepare to cross the border into Syria Getty Turkey launches offensive into Syria Civilians flee with their belongings AFP/Getty Turkey launches offensive into Syria Civilians flee during Turkish bombardment on Syria's northeastern town of Ras al-Ain in the Hasakeh province along the Turkish border on October 9, 2019. - Turkey launched a broad assault on Kurdish-controlled areas in northeastern Syria today, with intensive bombardment paving the way for an invasion made possible by the withdrawal of US troops. (Photo by Delil SOULEIMAN / AFP) (Photo by DELIL SOULEIMAN/AFP via Getty Images) DELIL SOULEIMAN AFP/Getty Turkey launches offensive into Syria Turkish President Recep Tayyip Erdogan, right, speaks with Defense Minister Hulusi Akar, left, as they watch the operation by Turkish forces in Kurdish areas EPA Turkey launches offensive into Syria Smoke rises from the Syrian town of Tal Abyad AFP/Getty Turkey launches offensive into Syria Turkey-backed members of Syrian National Army prepare for moving to Turkey with heavy armed vehicles EPA

No one claimed responsibility for the attack.

Turkey-backed opposition fighters took control of parts of Aleppo province, including the towns of al-Bab and Afrin, in previous military offensives in 2016 and 2018, respectively.

The past month's attacks have come amid an expanding Turkish invasion of into northeast Syria against Kurdish-held towns and villages along a stretch of the border.

Three car bombs went off Monday in the northeastern Syrian town of Qamishli near the border with Turkey, killing at least six people, according to activists and Syria's state news agency SANA.

On 2 November, a car bomb killed 13 people in the northern Syrian town of Tal Abyad, which is also held by Turkey-backed opposition fighters.

The Turkish offensive has aimed at pushing Kurdish fighters away from the border. Those Kurdish fighters had been key US allies in the fight against the Islamic State group. Turkey considers the Syrian Kurdish fighters terrorists linked to a Kurdish insurgency within Turkey.

Turkish forces have consolidated control over a stretch of the border running 70 miles wide and 20 miles deep into Syria. They have also kept up pressure outside that area, fighting with Kurdish forces on the edges.

Syrian government forces and their Russian allies have moved into other parts of the border under a Russian-Turkish deal.