Soviet troops invaded Afghanistan on 24 December 1979, launching a war which lasted a decade. The BBC has spoken to people on both sides about a conflict which marked their lives.
Afghan teacher Gelalei Habib was already living in fear of the communist regime when the USSR invaded her country 25 years ago. The disappearance of her little sister still haunts her.
During the [communist] government of Hafizullah Amin, I was an elementary school teacher and besides my normal job, I had some political activities too.
Gelalei Habib blames her country's woes on the communist years
One day I was at work when the agents from the interior ministry raided my home and searched everywhere. They seized my books. I was not there so they took my 13-year-old sister with them.
When I heard this news I realised that my life was in danger. I never went back to my house. I had to live secretly with my husband and two kids after that.
A very difficult period started in our life: we had to go from one home to another for more than three months. We were staying with our friends and relatives during this time.
I was worried for my sister Badrieh more than I was worried for myself. I did not know her whereabouts or what had happened to her. We have never been able to find her to this date. This is the most terrible bereavement in my life.
Sometimes I wish all the women in Afghanistan could remove their veils and I could see their faces - maybe I could find my sister among them?
When we were displaced we listened to the news every day just hoping to get good news, but on 27 December  we heard that our country had been occupied by foreign forces.
People were shocked to hear this for some time, but soon the resistance started. The Soviet forces were everywhere. They first controlled the country peacefully but when they saw the resistance, they intensified their crackdown.
One of the ways people used to fight the foreign forces was to go up on the roof and chant God Is Great. The Soviet soldiers used to shoot at them.
I think the Soviet invasion in Afghanistan, together with the [April 1978 communist] coup, was the source for all the miseries of the Afghan people who are seeing its consequences even today.
There is no family who, during this period, did not lose a relative or had someone maimed. I remained in Afghanistan for all this period. I continued to teach the children how to read and write privately, until the day that I could get back to my work.
Interviewed by BBCPersian.com.