Taliban militants killed Dawa Khan Menapal in the capital after warning they would target officials.
The director of Afghanistan’s media and information centre has been assassinated by Taliban militants in the capital, Kabul.
Dawa Khan Menapal was killed by gunmen on Darul Aman Road in the capital, reports said.
The Taliban said he had been “punished for his deeds”.
It came as local officials said that the southern city of Zaranj had become the first provincial capital to fall to the Taliban.
A government source told the BBC that the insurgents had taken the city in Nimroz province, on the border with Iran, on Friday. The source said fighting was still happening around the National Directorate of Security office.
The reports have not been officially confirmed.
Menapal’s killing came days after the Taliban assaulted the defence minister’s home in Kabul.
After the attack on Wednesday – the first major bombing by militants in the city for nearly a year – the Taliban warned of further attacks on government figures.
“Unfortunately, the savage terrorists have committed a cowardly act once again and martyred a patriotic Afghan,” interior ministry spokesman Mirwais Stanikzai said.
US Charge d’Affaires to Afghanistan Ross Wilson tweeted that he was “saddened and disgusted” by the killing, adding: “These murders are an affront to Afghans’ human rights and freedom of speech.”
The UN Security Council has called an open meeting for Friday on the situation in Afghanistan amid worsening violence.
Taliban militants have captured large swathes of the countryside and are now attacking key cities including Kandahar in the south, economically important Herat, and Lashkar Gar – capital of Helmand Province.
It comes after US and other international forces announced their withdrawal following two decades of operations.
Diplomats said Afghan government officials requested the meeting in view of the growing unrest. It is set to start at 10:00 local time (14:00 GMT) in New York, diplomats said.
On Thursday night US and Afghan forces launched air strikes on Taliban positions in Lashkar Gah.
Government troops have vowed not to lose the strategically significant town, and fighting there has been fierce. Officials have urged civilians to evacuate, with thousands trapped or fleeing for their lives.
Neighbouring nations are also set to discuss the situation in Afghanistan on Friday.
Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan have sent diplomats to Turkmenistan’s town of Avaza on the Caspian Sea for annual talks.
Turkmen President Gurbanguly Berdymukhamedov called Afghanistan “the question that worries us all” on Wednesday during a state television broadcast, AFP news agency reports.
Russia meanwhile has held military drills with Uzbek forces this week, amid growing concerns about security in the region – including the capture of key Afghan border crossings in the past month.
On Thursday the European Union called for “an urgent, comprehensive and permanent ceasefire” in Afghanistan as the “senseless violence” escalates.