At least six people have been killed by assailants wearing suicide vests who stormed a national television and radio station in the city of Jalalabad, in eastern Afghanistan, government officials say.

The attackers were carrying AK-47s when they entered Radio Television Afghanistan (RTA) on Wednesday in the latest assault on news media workers in the country.

The raid on the RTA state broadcaster was carried out by four attackers, one of whom had detonated a suicide bomb at the entrance to the compound, said Gulab Mangal, governor of Nangarhar.

As the attack unfolded, heavy gunfire was heard from around the RTA building, which is close to the governor's compound.

The three others were killed by security forces in the gun battle, Mangal said.

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The Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group claimed responsibility for the attack that comes over a week after the leader of ISIL in Afghanistan was killed in a US drone attack.

Al Jazeera's John Hendren, reporting from Kabul, said that 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.

Among the dead were four RTA employees, including a driver, a guard, and two technical personnel, as well as two policemen, according to Mangal.

ISIL has established a stronghold in Nangarhar, of which Jalalabad is capital, where it fights both the Taliban and Afghan government forces.

Last month, the US military dropped the GBU-43/B Massive Ordnance Air Blast bomb, dubbed the Mother Of All Bombs, on ISIL positions in Nangarhar, killing dozens of fighters.

The bombing was criticised by many in Afghanistan and abroad, saying that it amounted to using the country as a testing ground for the weapon.

Wednesday's attack underscores the growing dangers faced by news media workers in Afghanistan as the security situation worsens.

Dangerous for reporters

The country suffered its deadliest year on record for journalists in 2016, according to the Afghan Journalists' Safety Committee (AJSC), adding that the country is the second most dangerous for reporters in the world after Syria.

As least 13 journalists were killed last year, AJSC said, claiming the Taliban was behind at least 10 of the deaths.

In January 2016, seven employees of popular TV channel Tolo, which is often critical of fighters, were killed in a suicide bombing in Kabul in what the Taliban said was revenge for "spreading propaganda" against them.

It was the first major attack on an Afghan media organisation since the Taliban were toppled from power in 2001.

Dan Coats, head of US intelligence agencies, said last week that the security and political situation in Afghanistan "will also almost certainly deteriorate through 2018, even with a modest increase in the military assistance by the US".

US-led forces have been fighting in Afghanistan for almost 16 years, making it the US' longest war.