WASHINGTON (AFP) -- The U.S. reported significant progress in removing unexploded munitions left over from the recent Lebanon war, days after UN officials bemoaned the slow pace of efforts to find and neutralize mini-bombs dropped by Israel during the conflict.

"The effort to remove the unexploded ordnance is moving along very aggressively and we're really making a lot of progress," said Randall Tobias, the State Department's director of foreign assistance.

Tobias, who visited Lebanon late last month, said U.S.-funded teams had removed or assisted in the removal of about 50,000 pieces of unexploded ordnance left from the July-August war between Israel and the Hezbollah militia in Lebanon.

He said this was double the amount of munitions cleared over a two-year period in Kosovo following the 1999 conflict in the Serbian province.

Tobias did not provide details of the munitions removed by the U.S.-backed teams and was unable to give a precise estimate of the overall quantity of unexploded ordnance still scattered in Lebanon, other than to say he believed it to be around another 50,000 pieces.

But his portrayal of the progress being made contrasted with a UN complaint last week that Israel's failure to provide detailed maps of where its forces dropped so-called "cluster bombs" in Lebanon had hamstrung clearance operations.

The cluster bombs each spread hundreds of tiny bomblets designed to kill enemy troops. Thousands of the bomblets dropped onto southern Lebanon failed to explode on impact.

According to Israeli news reports, Israel dropped more than 1.2 million mainly U.S.-made bomblets on Lebanon during the month-long war.

Since a UN-brokered ceasefire ended the fighting on August 14, 22 people have been killed and 135 wounded by unexploded bomblets, according to an AFP count.

The United States has launched an investigation into whether Israel violated agreements restricting the use of US-made cluster bombs during the conflict. A State Department spokesman said Thursday that the probe was continuing.