An international rights group has called on the Afghan government and the international community to tackle the country's growing crisis of refugees internally displaced by war.

Amnesty International says in a report released on Tuesday that more than 1.2 million Afghans have been forced to flee their homes due to the violence in the past three years.

The report, released in the Afghan capital, Kabul, says the numbers are growing as the war, now in its 15th year, intensifies.

The report says many of the internally displaced "live in horrific conditions on the brink of survival."

The Taliban have intensified their insurgency across Afghanistan since the departure of most foreign combat troops in 2014. Last year, they briefly seized the northern city of Kunduz forcing thousands of people to flee.