The Mauritanian government has confirmed reports that several people have been arrested for planning a fresh coup against President Maaouiya Ould Taya.
Defence Minister Baba Ould Sidi told the state-run Mauritanian news agency AMI on Tuesday that the coup was due to have taken place as the president left for a visit to France on 14 August.
Ould Sidi did not say how many people had been arrested, but he said they were linked with the group of military officers that staged a failed putsch in June 2003.
A diplomatic source in neighbouring Senegal who monitors security issues in West Africa closely said about 40 people were arrested between Sunday night and Monday morning, including several civilians, but only a dozen of the detainees had so far been identified by name.
Last year's military uprising led to two days of fighting in the capital Nouakchott after which forces loyal to President Ould Taya regained control.
That coup attempt was led by Major Saleh Ould Hanenna, who escaped arrest and is still at large. And relatives of those arrested in the latest crackdown said they were all members of the same Awlad Nasser ethnic group as Ould Hanenna.
They said the detainees included three colonels and a major in the National Guard, a lightly armed division of the army charged with the protection of government buildings and important personalities.
The Awlad Nasser are light-skinned Bidan Moors from the region around Ayoun el Atrous, a town in southeastern Mauritania, 800 km from Nouakchott. However, the army high command is dominated by officers who like Ould Taya are light-skinned Bidan Moors from northern Mauritania.
The Bidan account for a minority of Mauritania's 2.5 million staunchly Muslim population, but ever since independence from France in 1960, they have formed the ruling elite. However, the Bidan are divided into various clans which vie with one another for power and influence.
Mauritania's population also consists of dark-skinned Harratin Moors, the descendants of former slaves, and black Africans with closer links to Sub-Saharan Africa than the Arab world and who generally live near the Senegal river in the extreme south of the country.
President Ould Taya, a former army colonel, seized power in a 1984 coup and has ruled this desert nation with a firm hand ever since, despite several attempts by dissident factions of the army to unseat him.
A total of 123 people are still in detention awaiting trial following last year's coup attempt, during which rebel tanks shelled the presidential palace in Nouakchott and silenced the radio and television stations for 24 hours..
The diplomatic source said Ould Taya must have had pretty hard evidence of a fresh attempt to overthrow him in order to undertake a fresh purge of the poorly paid army where morale is low and opposition to the president's policy of maintaining diplomatic relations with Israel runs high.
"I don't think they would have undertaken something like this unless they had very strong indications that something was afoot," the source said.
He dismissed suggestions by some opposition figures within Mauritania that the government had simply invented the coup plot to justify a further crackdown on its suspected opponents.
The source predicted that a deep malaise would continue within the armed forces, especially among officers from southern Mauritania who were bitter at their exclusion from power and the opportunities to engage in lucrative business which senior command positions afforded.
Woodside Petroleum, an Australian company which is developing an offshore oilfield in Mauritania, said in a statement on Tuesday that it had advised its staff and contractors to suspend travel to the country as a precautionary measure.
However, daily life continued normally in Nouakchott on Wednesday, with no signs of an increased presence of security forces on the streets.
The United Nations classifies Mauritania as being in phase one, the lowest category of its five-step system of security precautions. This allows all international staff to remain on station with their spouses and children. Phase five calls for the evacuation of all international staff from the country.