* Rebels hold high ground, loyalists in the desert plains
* Refugees say men taken from village of Ghezaya
* Rights group warns of indiscriminate attacks
By Matt Robinson
REMADA, Tunisia, May 10 (Reuters) - The woman took the call at a refugee camp in Tunisia.
Before the line went dead, her brother-in-law told her his son, her nephew, had been abducted in Libya's Western Mountains.
"He was taken from the mosque," the woman, who asked not to be named, said at a refugee camp in the Tunisian town of Remada. "Three other men were taken too, by Gaddafi's forces."
They disappeared last month from the village of Ghezaya, in the desert plains between flat-topped mountains just inside Libya's western border with Tunisia.
They have not been heard of since, and there has been no communication with the village, where residents are surrounded by troops loyal to Muammar Gaddafi, refugees and rebels say.
On Libya's western front, the rebels may hold the high ground, but there is mounting concern over the fate of villagers in the plains below.
This region, home to the Berber ethnic minority, was among the first to raise the rebel flag against Gaddafi, and now those who have fled fear for the safety of relatives and neighbours left behind.
"Some of these communities have refused to submit, and they are now paying a high price to be free," said Nadya Khalife of New York-based Human Rights Watch.
HRW said on Monday it had gathered credible accounts of indiscriminate shelling of rebel-held towns in the Western Mountains by pro-Gaddafi forces.
A Reuters reporter in the rebel-held town of Nalut saw what appeared to be the impact of mortar rounds on the front of a house and the grounds of a mosque.
The refugee camps, home to some of the 40,000 people who have fled, are rife with stories of livestock slaughtered, threats of rape and wells poisoned.
They are impossible to verify independently because of the restrictions facing journalists trying to reach the area.
Libyan officials deny attacking civilians, and say they are waging a battle against armed criminal gangs and al Qaeda sympathisers who, they say, are trying to destroy the country.
In the Western Mountains, "several families we spoke to said that some young men have not been seen or heard from for months," Khalife said.
The woman whose nephew was taken from the mosque said her sister and her family were still there, at least up until two weeks ago when she they last managed to speak.
"There is no news, no communication," she said.
"The whole of Ghezaya is under the control of Gaddafi forces. The rebels can't attack because there are civilians surrounded by Gaddafi forces." (Editing by Andrew Roche)