KABUL (REUTERS) - Suicide bombers and gunmen attacked a construction company office in the Afghan city of Jalalabad on Wednesday (March 6), killing 16 employees of the Afghan company, a provincial official said.

The attack began when two suicide bombers set off their explosives outside the company office and gunmen then opened fire, said Mr Attaullah Khogyani, a spokesman for the governor of Nangarhar province.

The 16 dead at the company included several of its guards. Five attackers were also killed - the two bombers and three gunmen, he said.

There was no immediate claim of responsibility.

Jalalabad is the capital of Nangarhar province, which is on the border with Pakistan.

It has become the main stronghold in Afghanistan of the Islamic State in Iraq and Syria (ISIS), which has grown into one of Afghanistan's most dangerous militant groups since it appeared around the beginning of 2015.

Mr Sohrab Qaderi, a provincial council member in Nangarhar said four employees of the company were taken to hospital and were in critical condition.

The bombings come as the United States and Taleban negotiations continue to hold ongoing peace talks in Qatar aimed at ending the nearly 18-year conflict.

Despite a two-day break before the weekend, negotiations continue on "a daily basis right now and progress is being made", US State Department spokesman Robert Palladino told journalists on Tuesday.

"These discussions are ongoing and what we're focusing on are the four interconnected issues that are going to compose any future agreement," Mr Palladino said - listing them as terrorism, troop withdrawal, intra-Afghan dialogue and ceasefire.

The continuation of the talks follows a major attack on a joint US-Afghan base in south-western Afghanistan's Helmand province last week, with at least 23 security forces killed in the hours-long assault on one of the largest military installations in the country.

Heavy snowfall across large swathes of Afghanistan has led to a sharp reduction in violence this winter, but warmer weather in the country's south will likely spark an increase in bloodshed, with the arrival of the spring fighting season.

Analysts have warned that the Taleban are likely to ramp up attacks in the coming months as it seeks to maintain momentum on the battlefield and leverage at the negotiating table.