Rebels say Saddam Hussein's forces have massacred an entire village and are strafing refugees from helicopter gunships in a terror campaign aimed at driving rebellious Kurds from Iraq.

Hundreds of thousands of Kurds fleeing the advance of Iraqi troops have clogged mountain passes leading to the Turkish and Iranian borders.Kurdish rebel leader Masoud Barzani charged Monday that Iraqi troops killed all of the 2,000 to 3,000 people who had populated Kara Henjir, a village near the key northern oil center city of Kirkuk.

"We still don't know the exact number," said Barzani, leader of the Kurdistan Democratic Party. "This was a deliberate move to terrorize the rest of the people into fleeing."

He said there were reports of other, similar atrocities by Iraqi troops but that rebel leaders could not confirm them.

Iran's official Tehran Radio said more than 750,000 Iraqi refugees have crossed the border into Iran, and the number was expected to exceed 1 million soon.

The radio quoted a refugee as saying in one case Iraqi helicopters fired at refugees along Iran's border as an American aircraft flew nearby.

"They (the U.S. crew) showed no reaction whatsoever," Mohammed Saleh Marouf, an engineer from Erbil, was quoted as saying.

The Kurdistan Democratic Party, in a communique from London, said Iraqi troops were constantly firing on fleeing Kurds.

None of the rebel claims could be independently verified by foreign reporters in northern Iraq.

As Barzani spoke to reporters in the mountains north of Erbil, thousands in the region were abandoning their homes to trek toward Iran.

Foreign governments and aid groups are running a huge relief operation to save the refugees, many of whom are sick, hungry and cold.

Britain on Monday proposed creation of a U.N.-protected refugee zone in northern Iraq - a plan welcomed by Barzani but rejected Tuesday by Iraqi Prime Minister Saadoun Hammadi.

A night of hail, thunder and lightning worsened the refugees' plight Tuesday. Officials said scores must have died from exposure during the night.

Thousands of trucks, cars and other vehicles were packed solid and motionless along the mountain roads. Thousands of other refugees trudged past, many barefoot, on a several-days trip to the border.

Rebel officials said Tuesday aid airlifted by the United States, France and Britain had fallen near the Turkish border, but none reached hundreds of thousands of refugees massed near Haj Omran, a border crossing into Iran.

Iraq has protested the airlift as a violation of its territorial sovereignty.