The treatment of the Bulgarian nurses in Libyan prisons has caused concern

Libyan ties with the West have improved in recent years and Human Rights Watch was allowed to visit the country for the first time and meet officials.

HRW acknowledged that the authorities had embarked on reforms, but it says torture and unfair trials continue.

It says severe restrictions on free speech are common and many Libyans are imprisoned for their political views.

Executive Director Kenneth Roth told the BBC the Libyan government was at first disappointed and critical when their findings were presented to them,

But he said they were able to engage in long discussions, despite their disagreements.

Torture

"The main problem we have documented is cases of torture. We interviewed 32 people in the prisons and 15 of them complained they had been tortured to make a confession," he said.

Human Rights Watch also criticised the United States and European countries for ignoring a lack of rights in Libya, in favour of focusing on security and economic ties with Muammar Gaddafi's government.

The 85-page report compiled after a three-week visit to Libya in spring 2005 called Libya a "country undergoing gradual change after years of strict repression and global isolation".

It said "scores of individuals are in prison for peacefully expressing criticism of the government or alternative political views".

And it called for the release of 131 political prisoners, including more than 80 who have been held since the 1980s. Fourteen were recently released.