The Taliban has taken over Afghanistan’s second biggest city of Kandahar, officials said on Friday, fuelling fears the US-backed government could fall to the insurgents as international forces complete their withdrawal after 20 years of war.

The city was reportedly seized on late Thursday as the Taliban continues to step up their offensive amid US troops’ withdrawal. The pullout was stipulated in the deal the Taliban and the US agreed upon in Doha in February last year.

Kandahar is the heartland of the Taliban, ethnic Pashtun fighters who emerged in the province in 1994 amid the chaos of civil war to sweep through most of the rest of the country over the next two years.

The Taliban also captured the towns of Lashkar Gah in the south and Qala-e-Naw in the northwest, security officers said. Taliban on Thursday also claimed to have captured the third-largest city of Herat in the west after days of clashes there.

Government forces were still in control of Kandahar’s airport, which was the US military’s second biggest base in Afghanistan during their 20-year mission. Lashkar Gah is the capital of the southern opium-growing province of Helmand, where British, US and other foreign forces battled the insurgents for years.

According to FDD’s Long War Journal, the Taliban have claimed the seizure of more than 10 out of 34 administrative centers of Afghan provinces.

The Taliban began its offensive in May and swiftly began seizing key districts. More than 160 districts have fallen, in addition to an estimated 73 districts that were controlled by the Taliban before the offensive began, Long War Journal reported.

The terrorist group now controls eight of Afghanistan’s 34 provinces in their entirety, it added.

Meanwhile, a group of participants in the Afghan peace talks that took place in Doha, Qatar, issued a joint statement on Thursday, calling for accelerating the peace process between the government of Afghanistan and the Taliban.