US Defence Secretary Donald Rumsfeld has warned that any attempt by Iraq to deploy people as "human shields" in the event of war will be regarded as a war crime.
Volunteers are flocking to Iraq
His comments come as growing numbers of Western volunteers arrive in Iraq to act as human shields, in an attempt to prevent a US-led war.
Mr Rumsfeld accused Iraqi leader Saddam Hussein of making no distinction between combatants and innocent civilians.
"He deliberately constructs mosques near military facilities, uses schools, hospitals, orphanages and cultural treasures to shield military forces, thereby exposing helpless men, women and children to danger," he told reporters at the Pentagon in Washington.
The principle that civilians must be protected lies at the heart of international law of armed conflict
"These are not tactics of war, they are crimes of war. Deploying human shields is not a military strategy, it's murder, a violation of the laws of armed conflict, and a crime against humanity, and it will be treated as such."
The United States has already threatened to prosecute any Iraqi military leaders who use chemical or biological weapons.
Mr Rumsfeld made it clear that the same conditions applied to human shields.
"Those who follow his (Saddam Hussein's) orders to use human shields will pay a severe price for their actions," he said.
Dozens of volunteer human shields in a convoy of vehicles, including double-decker buses, arrived in Baghdad this week after travelling from London. Others are flying to Amman in Jordan before making their way overland to Iraq.
General Richard Myers, Chairman of the Joint Chiefs of Staff, said that intentionally placing civilians in danger was illegal.
General Myers said: "It is a violation of the law of armed conflict to use non-combatants as a means of shielding potential military targets - even those people who may volunteer for this purpose."
The term "human shields" became common currency before the Gulf War in 1991, when Saddam Hussein threatened to place Westerners detained in Iraq at sites deemed likely to be attacked by the US-led coalition.
He did not carry out this threat, and most of the detainees were released before hostilities began.