Hundreds of Afghans protested on Saturday against the killing of a teenage boy by NATO-led forces in a volatile eastern province, and the district governor said one man was shot dead as police fired at the crowd.

District governor Abdul Khaliq Mahroof told Reuters demonstrators had poured into the streets in the Hesarak district of eastern Nangarhar province to denounce the overnight killing of a 15-year-old boy by Afghan and foreign troops.

Mohammad Balal, the son of an Afghan soldier, was killed on Friday night in Hesarak town, as foreign forces were carrying out an operation.

Hundreds of angry Afghans have staged a protest in Hesarak district of Nangarhar province against the killing.

"It all started with hundreds of demonstrators throwing stones and later firing weapons," Mahroof said, adding that the protest had now ended.

"The police had to fire back at some of the protesters who were armed and one was killed and three wounded."

Hesarak borders Kabul province and lies some 70 km (40) miles southeast of the capital.

In a statement issued early on Saturday, the NATO-led International Security Assistance Force (ISAF) said its troops had "mistakenly killed" a 15-year-old boy during an operation with Afghan forces to capture a Taliban fighter in Hesarak.

"As a force protection measure, a security force member engaged the individual, resulting in his death. After initial assessment, it was discovered the individual was a local 15-year old male," ISAF said.

The teenager's killing was the second such incident this week. On Thursday, Afghan and foreign troops killed a policeman and a girl during a raid on their compound, also in Nangarhar.

Hundreds of Afghan civilians have lost their lives in US-led airstrikes and ground operations in various parts of Afghanistan over the past few months.

A U.N. report this year showed that 2010 was by far the most lethal for Afghan civilians with a total of 2,777 civilians killed, up 15 percent on the previous year.

Agencies