Gunmen stormed the national television and radio station in the eastern Afghan city of Jalalabad, triggering a gunfight as journalists remained trapped inside the building.
The attackers, which carried AK-47s, entered Radio Television Afghanistan (RTA) on Wednesday and engaged in a gun battle with security forces.
Two of them detonated their vests, while at least one – possibly two – remained to fight, police said.
“Three attackers are dead and so are three other people, including one policeman,” Al Jazeera’s John Hendren, reporting from Afghanistan’s capital, Kabul, said, quoting police officials.
At least 16 people, including journalists, were wounded in the attack, which took place in central Jalalabad, close to the provincial governor’s office and a busy square, Hendren said.
There was no immediate claim of responsibility for the attack.
Jalalabad is the capital of Afghanistan’s Nangarhar province, on the eastern border with Pakistan.
Khorasan, an affiliate of the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) armed group, has previously launched attacks in the province.