Kabul (Web Desk): At least 18 people were killed in a suicide car blast in the eastern Afghan city of Khost on Saturday, officials said, in the first major insurgent attack at the start of the holy fasting month of Ramazan.

According to details, no group has so far claimed responsibility for the bombing, which provincial authorities said targeted Afghan security forces working with American troops in Khost province.

The recent attack is the latest in a series of attacks on Western-backed forces as the Taliban step up their yearly spring offensive and the insurgency expands more than 15 years after they were toppled from power in a US-led invasion.

Interior ministry spokesperson Najib Danish said, “A suicide car bomb in Khost province has killed 18 people and wounded six others, including two children.”

“The target was a public bus station which was hit by the bombing. The victims were in civilian clothes and it is difficult to verify their identities at this stage.”

However, provincial police chief Faizullah Ghairat said the victims were civilians and members of the elite Khost Provincial Force (KPF) working with US troops.

Ghairat told a foreign agency, “The bombing took place early morning when KPF members were heading to work.”

The blatant attack comes just a day after Taliban fighters attacked that left at least 15 Afghan soldiers dead in Kandahar, in the third major insurgent assault this week on the military in the southern province.

Earlier this week insurgent raids occurred insurgent raids on military bases in the same area and Maiwand district, bringing the death toll among Western-backed troops to around 60 and later the assault in Shah Wali Kot district.

In late April, the Taliban launched their annual spring offensive, herald a surge in fighting as the US tries to craft a new Afghan strategy.

Last month, US Defense Secretary Jim Mattis warned of “another tough year” for security forces in Afghanistan.

The several NATO allies and USA are considering sending thousands more troops to break the stalemate against the resurgent militants.