The attack comes just days after President Donald Trump announced his new strategy for Afghanistan, which involves maintaining a US military presence in the country and upending a campaign vow to end America's longest war.
According to Omar Zwak, the spokesman for the Helmand provincial governor, today's explosion in Lashkar Gah, the provincial capital, also wounded 42 people, mostly civilians.
Initial reports show that those killed included a small girl, two women and four soldiers, Zwak said, expressing fears that the death toll could rise further.
"This is from our initial reports, I am afraid the casualty tolls might change once we get a final report form the attack," he added.
The bombing took place near the police chief's headquarters. Local TV broadcast footage showing several military Humvees, which the Afghan army also uses, destroyed as a result of the attack.
Taliban spokesman Zabihullah Mujahid claimed responsibility for the attack in a posting on his twitter account.
Senior Afghan government officials yesterday welcomed Trump's strategy announcement from Monday. Senior US officials said Trump may send up to 3,900 more troops, with some deployments beginning almost immediately.
Trump also had harsh words for Pakistan, accusing Islamabad of giving extremists a safe haven, while next door in Afghanistan they kill US troops. He said he wanted "immediate" results without saying what actions the United States might take against Pakistan if it ignored his warning.
The United States and Afghanistan have routinely accused Pakistan and particularly its powerful intelligence agency of harboring insurgents and of waging a selective war, attacking those militants Islamabad considers its enemy and allowing those it has been known to use as proxies, either against hostile neighbors India or Afghanistan, to flourish.
Taliban attacks have stepped up all across Afghanistan since the withdrawal of foreign combat forces from the wartorn nation at the end of 2014, and the insurgents have lately been constantly expanding their footprint.
Earlier this month, the Taliban in an "open letter" to Trump, reiterated their calls for the withdrawal of all remaining US troops. The United States has about 8,400 troops in Afghanistan, who support local forces and carry out counter-terrorism operations.