The U.S.-led coalition says its troops have killed more than 100 militants during three days of fighting in southern Afghanistan.

In a statement Thursday, coalition officials said Afghan and coalition forces were on patrol in Helmand province Monday, when they were attacked several times by militants using gunfire, rocket-propelled grenades, and mortars.

Coalition officials say troops returned fire and called in air support.  The fighting continues today.

Earlier, the Afghan defense ministry said Afghan troops were engaged in clashes with militants in the Nad Ali district of Helmand.  Several militants were reported killed.

Also, Danish military officials today said Danish troops had witnessed Afghan soldiers shooting and killing an Afghan detainee Wednesday in Helmand.  Danish media reports the Afghan prisoner had been in British custody.

Separately, Afghan officials say Afghan security forces have begun taking over command of the the capital, Kabul, from NATO forces. 

Officials say the security hand-over is a largely symbolic move to reflect the growing strength of Afghan troops.

Afghan President Hamid Karzai announced the measure earlier this summer.  Foreign troops will continue to patrol parts of Kabul.

There are currently close to 60,000 troops in the Afghan army, and that number is expected to grow.

Also today, President Karzai condemned the killing of a Japanese aid worker, calling it a cowardly act.

Some information for this report was provided by AFP and AP.