The U.S.-led coalition in Afghanistan also known as the International Security Assistance Force (ISAF), formally ended its combat mission on Sunday with a ceremony held in secret due to the threat from the Taliban.
About 13,000 foreign troops, mostly Americans, will remain in the country under a new, two-year mission named "Resolute Support" that will continue the coalition's training of Afghan security forces.
In a statement US President Barack Obama said: "Now, thanks to the extraordinary sacrifices of our men and women in uniform, our combat mission in Afghanistan is ending, and the longest war in American history is coming to a responsible conclusion."
Five service members of the International Security Assistance Force in Afghanistan have been killed in a helicopter crash in the south of the country, said ISAF.
ISAF did not say what nationalities were involved, adding it was "still in the process of reviewing the circumstances to determine more facts".
The International Security Assistance Force (ISAF) said that a gunman has been killed following an attack in west Afghanistan, in which an Italian ISAF service member died.
The International Security Assistance Force (ISAF) has said it is investigating an insider attack, in which a US ISAF civilian was killed in eastern Afghanistan.
ISAF has also said that the incident in western Afghanistan was not an "insider attack".
Brigadier General Gunter Katz said today has been a "very difficult day" for ISAF after four of its service members died in two separate attacks in Afghanistan:
An Italian soldier has been killed and three others were wounded in an insurgent attack in western Afghanistan earlier today, Italy's Defence Ministry announced.
A spokesperson said the attack in Farah province came as the Italian soldiers were returning to their base after training Afghan security forces.
The Italian convoy of three armored vehicle had been slowed by traffic near an intersection when an attacker ran up and threw an explosive device into the lead vehicle, the ministry said.
The injuries of the three wounded soldiers were not life-threatening, it added.
The International Security Assistance Force (ISAF) confirmed earlier that there had been an insurgent attack in the region, but it did not provide details of the soldier's nationality in line with protocol.
The International Security Assistance Force (ISAF) has confirmed three of its service members were killed when someone wearing an Afghan National Army uniform turned their weapon on them.
ISAF said in a statement:
Three international soldiers were killed in eastern Afghanistan today in an apparent "insider attack", a spokeswoman for Afghanistan's NATO-led force told Reuters.
The spokeswoman said a man dressed in an Afghan government army uniform turned his weapon on them in the eastern province of Paktika.
She did not divulge the nationality of the three soldiers in line with protocol.
The International Security Assistance Force (ISAF) said it is investigating two separate attacks in Afghanistan today.
One was an "insurgent attack" which took place in western Afghanistan, the other is a possible "insider attack" in eastern Afghanistan:
No further details were given.
The International Security Assistance Force (ISAF) said it is investigating a possible "insider attack" in eastern Afghanistan which resulted in three deaths:
ISAF did not provide the names or nationalities of those killed, which is in line with protocol.