BY AZIZ EL YAAKOUBI
(Reuters) - Tunisian state media said the head of the country's Islamist militants had been captured in Libya by U.S. and Libyan forces on Monday, though his organization denied he had been detained.
The U.S. army also said it had not played any part in any move against Ansar al Sharia leader Saifallah Benahssine - the man accused of inciting an attack on the U.S. embassy in Tunisia in 2012.
Any U.S. involvement in an operation on Libyan soil would be highly sensitive. Libyan Islamists were furious at what they saw as Washington's interference after American forces captured a top al Qaeda suspect in Tripoli in October.
If confirmed, the capture of such a high-ranking Tunisian militant in Libya would also highlight close ties between Islamist groups in North Africa.
After the fall of Muammar Gaddafi two years ago, Libya has drawn foreign militants because its weak central government, uncontrolled southern areas and porous borders to sub Saharan Africa allow arms and fighters to flow to regional hot spots.
Western powers have pledged to help Libya control its frontiers and train its nascent armed forces to build up its capacity to control the country's territory.
Tunisia's TAP agency, citing a senior security source, said Benahssine, also known as Abu Iyadh, had been arrested in the coastal city of Misrata on Monday morning.
"An authorized security source told TAP that Saifallah Benahssine, known as Abu Iyadh, has been arrested in Libya on Monday morning," TAP said.
"The source said special American forces arrested Abu Iyadh and other members of his group, helped by Libyan forces."
The U.S, military said it had played no part in any operation, and U.S. security officials told Reuters that U.S. intelligence agencies and their personnel also were not involved.
Some U.S. officials believed that Abu Iyad had indeed been captured, while others said that reports of his capture had not been confirmed and cannot be considered reliable.
Libya's LANA state news agency also published the TAP report on the capture. But there was no comment from the Libyan government.
Misrata officials denied he had been captured in their city.
"Ansar al-Sharia in Tunisia denies any information stating that its prince, the Tunisian Abu Iyadh, may God protect him, has been captured," the group said on its Twitter account.
Ansar al-Sharia was one of the hardline jihadist groups to emerge after the Tunisia's revolt against its autocratic leader Zine al-Abidine Ben Ali three years ago when long-oppressed Islamist ultra-conservatives rose in influence.
Militant violence has also increased there since the government began a crackdown on the group this year, declaring it an outlawed organization.
(Additional reporting by Ghaith Shennib and Ulf Laessing in Tripoli; Writing by Patrick Markey; Editing by Andrew Heavens)