UPDATE 4-Blast near US convoy kills Afghan, wounds scores

* Blast kills child, wounds scores of civilians

* Most of wounded children

(Adds U.S. military issuing photos of grenade fragment)

By Amin Jalili

ASADABAD, Afghanistan, June 9 (Reuters) - A blast near a stalled U.S. troop convoy in eastern Afghanistan killed one child and wounded scores of civilians and three U.S. soldiers on Tuesday, Afghan officials and the U.S. military said.

Some witnesses and the Afghan Education Ministry initially blamed a U.S. soldier for throwing a grenade into a crowd, but the U.S. military said the grenade was Russian-made and had been thrown by an insurgent.

Asadabad hospital doctor Ehsanullah Fazli said most of the wounded were children. Some were in critical condition, he said.

The military said in a statement that up to 54 Afghan civilians had been wounded in the incident in Asadabad, capital of Kunar province in the east. It issued photos of what it said was a grenade fragment with Russian serial numbers.