American forces have experienced their deadliest month in the nine-year-old Afghan war.
Three more US-led soldiers have been killed in southern Afghanistan, bringing the July death toll among foreign troops in the country up to 91.

NATO's International Security Assistance Force (ISAF) said in a statement on Saturday that the troops were killed in a number of explosions on Friday.

The Western military alliance has not yet revealed exact location of the explosions or the nationalities of the dead soldiers; but US military sources say they were American.

The deaths come one day after three other US soldiers were killed in southern Afghanistan.

July has been the deadliest month for American forces in Afghanistan to date. Over 90 foreign troops -- 66 of whom, were American -- have lost their lives in the war-torn country this month, alone.

Roadside bombs, or Improvised Explosive Devices, (IEDs) are by far the most lethal weapons the Taliban militants have used against the foreign troops.

The American army has lost 1, 209 soldiers since October 2001 when the United States spearheaded the invasion of Afghanistan to overthrow the Taliban militants.

Since that time, thousands of civilians have lost their lives and many others sustained injuries in NATO operations in the country.