The increase reverses a decline in 2012 and raises questions about how Afghan government troops can protect civilians as US-led NATO troops withdraw from the 12-year war against the Taliban.
The UN Assistance Mission in Afghanistan (UNAMA) said 1,319 civilians died and 2,533 were injured as a result of the war from January 1 to June 30, up 23 percent from the same period in 2012.
UNAMA said there was a 14 percent increase in total civilian deaths and a 28 percent increase in total civilian injuries.
"The rise in civilian casualties in the first half of 2013 reverses the decline recorded in 2012, and marks a return to the high numbers of civilian deaths and injuries documented in 2011," it said.
The UN said 74 percent of the casualties were caused by insurgents, nine percent by pro-government forces and 12 percent as a result of ground fighting between the two sides.
The remaining four or five percent of civilian casualties were unattributed, caused mainly by explosive remnants of war, it added.
Insurgent bomb attacks remain the highest cause of civilian casualties, but increased ground fighting between Afghan troops and insurgents was the second leading cause.
Many civilians also have fallen victim to US-led forces attacks in the war-torn country.
The United States and its allies invaded Afghanistan in 2001 as part of Washington’s so-called war on terror. The offensive removed the Taliban from power, but insecurity remains high in the country.
BA/BA