Insurgents and government forces inflicted a "human rights catastrophe" in parts of southern Yemen earlier this year in a struggle that saw an al-Qaeda linked group carry out amputations and a crucifixion, Amnesty International said on Tuesday.
The turmoil in Abyan province, one of the worst episodes of lawlessness in a country suffering multiple internal conflicts, has worried neighboring oil power Saudi Arabia and is seen by the West as a threat to shipping lanes in the seas off Yemen.
Amnesty demanded that the abuses in the southern province be examined by an inquiry announced in September by the government into alleged rights violations during a popular revolt against former President Ali Abdullah Saleh in 2011.
A U.S.-backed Yemeni military offensive drove Ansar al-Sharia (Partisans of Islamic Law) from southern cities and towns in June, nearly a year after the militant group captured swathes of Abyan after last year's popular uprising, which eventually forced former President Ali Abdullah Saleh to step down.
In a report entitled "Conflict in Yemen: Abyan's Darkest Hour," Amnesty accused the Islamist Ansar al-Sharia, one of a number of Yemeni militant groups linked to al Qaeda, and the Yemeni government of "gross and deeply disturbing abuses".
"Abyan experienced a human rights catastrophe as Ansar al-Sharia and government forces vied for control of the region during 2011 and the first half of 2012," said Philip Luther, Amnesty's director for the Middle East and North Africa.
"The tragedy of Abyan will haunt Yemen for decades to come unless those responsible are held to account, and victims and their families receive reparations."
Amnesty said it had documents showing that "religious courts" set up by Ansar al-Sharia had frequently imposed cruel, inhuman and degrading punishments on alleged criminals and suspected spies working against it in the city of Jaar.
EXECUTIONS, AMPUTATION, FLOGGING
One of those, named as Saleh Ahmed Saleh al-Jamli, 28, was killed and his remains crucified after one of those courts in Jaar found him guilty of planting electronic devices in two vehicles carrying Ansar al-Shari'a commanders.
The rights group also said that the militants also conducted public summary executions, amputation and flogging during their rule of Jaar.
Amnesty also accused Yemeni government forces of using excessive force in its fight against al Qaeda.
"Yemeni government forces used inappropriate battlefield weapons such as artillery in civilian residential areas, and in other attacks failed to take necessary precautions to spare civilians," the Amnesty report said.
A Yemeni army officer, who spoke on condition of anonymity, said the military had no choice but to use artillery to pummel the Islamist militants as they took refuge in government buildings.
"We had to stop the expansion of the armed groups and free towns under their control," the officer said.
A spokesman for the Yemeni embassy in Washington, Mohammed al-Basha, said in a statement: "The Yemeni government will carefully examine the findings of Amnesty International's most recent report."
Amnesty called for "an immediate and impartial investigation" into the violations.
The rights group said the fighting, which included U.S. backing with intelligence information and drone strikes, led to the displacement of nearly 250,000 from the southern provinces which were affected by the conflict.
Despite being routed from southern strongholds, al Qaeda in the Arabian Peninsula (AQAP) continues to pose a major threat to Yemen. The group has carried out a number of suicide bombings since June targeting military and security facilities and senior officials.
(Reporting by Mohammed Mukhashaf; Writing by Mahmoud Habboush; editing by Sami Aboudi and William Maclean)