New Delhi, Sep 25 (IANS): Around 20,000 Indians have urged Prime Minister Narendra Modi to ask the US to investigate cases of civilian deaths in Afghanistan caused by the country's military operations, a statement said Thursday.

As part of an Amnesty International India campaign, the group wants US President Barack Obama to ensure accountability for human rights violations and apparent war crimes in Afghanistan by US forces.

Modi is scheduled to meet Obama for summit-level talks in Washington Sep 29-30.

"The families of thousands of Afghan civilians killed by US and NATO forces are still waiting for justice. Modi must call on the US government to investigate cases where Afghan civilians have been killed in US military operations," said Shailesh Rai, programmes director, Amnesty International India.

Documenting the lack of accountability for civilian casualties caused by the US and NATO forces in Afghanistan between 2009 and 2013, a report by Amnesty titled "Left in the Dark" found that even apparent war crimes have gone uninvestigated and unpunished mainly because of the flawed US military justice system.

"The US government must address the unlawful killings of civilians by its forces," said Rai.

"As a key ally of both Afghanistan and the US, India must urge the US to ensure justice and remedy for Afghan civilians," he said.

Amnesty International India also urged Modi to raise other crucial human rights issues with the US authorities during his visit, including the Dow Chemical Company and Union Carbide's disregard for the Indian court summons over the 1984 Bhopal gas tragedy.