The suicide attack took place early afternoonin Bagram district Parwan province some 60 km north of capital Kabul the district chief Abdul Shakoor Qudoosi told Anadolu Agency adding that six foreign forces were killed and six others including three Afghan policemen were wounded in the incident.

The Taliban militant group claimed responsibility for the attack.

U.S. Secretary of Defense Ash Carter expressed his regret in a statementfor the six American soldiers being killed and two others wounded in the incident.

"We are still learning all of the details but two other service members and a U.S. contractor were also injured. They died after a vehicle-borne improvised explosive device attack on their patrol outside Bagram Air Base. It serves as a painful reminder of the dangers our troops face every day in Afghanistan" Carter said.

The attack came just after Carter's visit to the country last Friday.

Meanwhile a U.S. army veteran was shot dead in her residence in Kabul on Sunday evening. According to Afghan police officials she was killed by a mullah who was later arrested.

Two rockets landed -- one in NATO headquartersand the othernear the presidential palace in the capital Monday evening. There were no reports of casualties.

In the volatilesouthernHelmand province the Talibancapturedthe district of Sanginand besieged over 100 policemen. This comes after Helmand’s deputy governorMohammad Jan Rasoulyar said that the situation in Helmand was dire and thatif immediate action was not taken the entire province could fall underTaliban control.

"Around 90 Afghan soldiers lost their lives in the past two days in Sangin and Girishk districts and more would fall prey [to the Taliban]if the situation goes out of control"Rasoulyar said.

However officials in Kabul rejected the fall of Sangin saying severe clashed took place between security forces and the Taliban and that the district center and other government buildings were still in the control of security forces.

"At least 59 Taliban militants have been killed in the district"said Ministry of Defense spokesmanDawlat Waziri .

Top security official Mohammad Rasool Zazai said fighting between security forces and insurgents were still underway and certaincheckposts were recaptured.

On Dec.9 the Taliban overran Helmand'sKhanshin district center after fierce clashes with security forces.

Karim Atal the provincial council chief had said security personnel could not resist the Taliban attacksand that they had to retreatto an army base some three kmfrom the district center.

He said the Khanshin police chief had been seriously injured in the battle.

The situation in Musa Kala and other districts of Helmand has been steadily deteriorating worryingprovincial authorities.

RecentlyRasoulyar Helmand's deputy governorwrote an open letter -- which was also published on social media website Facebook -- to the president and informed him about the overall security situationof the province.

U.S. and British Special Forces were re-deployed in Helmand to fight alongside Afghan partners against Taliban militants gaining ground in the province.

U.S. and British troops had ended their combat mission in 2014handingover all of their bases to Afghanistan's security forces in Helmand province.

A month back the Taliban captured the Marja district of Helmand blocking all routes to the town and took control of major government buildings.

Chief Executive Officer (CEO) Abdullah Abdullah on Monday held an emergency Cabinet meeting and said the government was fully aware of growing insecurity and unstable situations in Helmand.

He said the situationwould improve in the near future as strict security measures had been put in place.

Helmand is a strategicprovince. Insecurity and Talibancontrol of parts of the province helped strengthen the insurgents and contributed to the production of poppy.

U.S. Secretary of Defense expressed his regret in a statementfor the six American soldiers being killed and two others wounded in the incident.

"We are still learning all of the details but two other service members and a U.S. contractor were also injured. They died after a vehicle-borne improvised explosive device attack on their patrol outside Bagram Air Base. It serves as a painful reminder of the dangers our troops face every day in Afghanistan" Carter said.

The attack came just after Carter's visit to the country last Friday as a part of his regional trip to visit U.S. forces in the region.