KABUL -- At least nine people, including three assailants, were killed and 22 others wounded in three separate suicide bombings in Afghanistan on Saturday, authorities said.

In one attack, one intelligence agency officer was killed and 16 civilians injured after a terrorist detonated a truck bombing in front of a provincial intelligence office in Lashkar Gah city, capital of southern Helmand province.

Those among the injured were 13 children and two women in the blast which occurred around 9:00 am local time and also damaged several nearby buildings.

The deadly explosion followed an blast in national capital of Kabul during which one civilian and two security forces died and five people injured.

The bombing came when a man wearing a suit tried to enter the Green Zone but detonated his explosive jacket after being identified by security forces in a security checkpoint in Shash Darak, a diplomatic district in central Kabul, an Interior Ministry spokesman Nasrat Rahimi told local Tolo News TV.

The Islamic State (IS) terrorist group reportedly claimed responsibility for Kabul attack.

Earlier on Saturday morning, a militant detonated an explosive-laden hijacked military armored vehicle at an army camp in Nad Ali district, west of Lashkar Gah, killing two soldiers and injuring another one, according to Rahimi.

Taliban militant group has claimed responsibility for attacks in Helmand province which is notorious for growing poppy and militancy.

The attacks came one day after the country started construction of a major gas project in western Herat province to transfer natural gas from Turkmenistan to neighboring Pakistan and India.