KABUL: A new study says civilian and military casualties in Afghanistan and Pakistan total almost 149,000 people killed, with 162,000 seriously wounded.

The study, called Costs of War and produced by Brown University's Watson Institute for International Studies, looks at war-related deaths, injuries and displacement in Afghanistan and Pakistan from 2001 to last year, when international combat troops left Afghanistan.

It says war in Afghanistan since the 2001 US-led invasion overthrew the Taliban regime has killed almost 100,000 people, and wounded the same number.

Noting a rise in annual figures for killed and wounded in recent years, the report's author, Neta Crawford, says the war in Afghanistan “is getting worse".

The United Nations said civilian casualties rose 16 per cent in the first four months of 2015, with 974 people killed.

While military deaths are logged with precision, Crawford said, civilian figures are difficult to source.

The report's figures are based on statistics from the United Nations Assistance Mission in Afghanistan, as well as other sources, she said.

Most civilian deaths happened after 2007, with more than 17,700 civilian deaths recorded by UNAMA between 2009 and 2014.

Most civilians were killed by militants, she said. Breaking the figures down, the report finds that 26,270 Afghan civilians have been killed and 29,900 injured as a direct consequence of the war.

The overall figure includes civilians, Taliban and other militants, US and allied forces, aid workers and journalists.

A downward trend in civilian deaths that began in 2008 had reversed, she said, and last year it became clear that insurgents were not distinguishing between civilian and combatants. Deaths that are impossible to attribute have also begun to rise.