Around 25,000 people have rallied in the Afghan capital Kabul, calling for a proposed war crimes amnesty for former military commanders to be made law.
Supporters say future peace depends on the amnesty
The protesters, who gathered in a stadium, included ex-mujahideen and several top government officials.
The upper house of parliament has passed the controversial bill but it has yet to be signed by the president.
Tens of thousands of people were killed and tortured during decades of war and unrest in the country.
If the bill were to become law, those who led fighting first as leaders of the anti-Soviet resistance during the 1980s and then during the 1992-1996 civil war would be immune to prosecution for war crimes.
International rights groups and the UN have voiced opposition to the proposal, saying justice must be done.
The protesters, waving placards with pictures of political leaders, gathered in the city's Ghazi football stadium, where people were executed and tortured during the Taleban era.
"Whoever is against mujahideen is against Islam and they are the enemies of this country," former fighter Abdul Rasul Sayyaf, now an influential lawmaker, told the crowd of demonstrators.
Mr Sayyaf is one of several commanders linked to human rights violations committed during the country's civil war.
The rally was also attended by former President Burhanuddin Rabbani, as well as current Vice-President Karim Khalili and Energy Minister Ismail Khan.
Youths later marched through the streets of the city, shouting "Death to the enemies of Afghanistan!" and "Death to America!".
More than a million people died during the war between Soviet-backed rulers and the mujahideen opposition.
President Karzai is known to oppose the proposal
Tens of thousands were killed during the civil war that followed as mujahideen factions turned on each other and under the hard-line Islamic Taleban regime that subsequently took power.
In the warlord period, some 80,000 civilians died in Kabul alone. Large numbers of others were kidnapped, mutilated or raped.
President Hamid Karzai is known to be opposed to the bill. He has said he will hold consultations before deciding whether to pass the legislation.
Some MPs in the lower house, which passed the bill last month, now say they did not understand its implications when they voted for it.
Supporters of the amnesty say it is a move towards reconciliation. They say if it does not happen there will be more war.
The United Nations and Afghan's leading rights groups say only victims of war crimes can forgive the perpetrators.