Lance Corporal Sanna Fadera was arrested a week ago after the government accused him of masterminding an attempted coup.

Two more officers were detained over the weekend, the government said.

This brings to seven the number of arrests over the alleged plot.

None of the accused has as yet been charged in court.

In a BBC interview, Alia Fadera, the eldest sister of the lance-corporal, said he could not have plotted a coup, as he was only a medic in the navy with no access to weapons or influence in the military.

"Since my brother's arrest, we have not heard from him and we are worried," she added.

Mrs Fadera said the military had detained her brother at his workplace in the capital, Banjul, before bringing him to their village in Kiang Nema, 155km (96 miles) away.

"His house and farm were searched by the military but no weapon was found," she added.

Mrs Fadera said her brother had lived in the village with his wife and four children, who were devastated by the allegation against him.

He travelled to and from work daily and ran a reptile farm in his spare time.

"The entire village is surprised and when the military truck came, most of the villagers came out to see what was happening. I'm calling on the authorities to release my brother," Mrs Fadera said.

Meanwhile, the government named the latest officers to be arrested as Capt Ebrima Baldeh, from the military intelligence unit, and Lt Omar Colley, from the First Infantry Battalion.

The government added that it had set up a panel - made up of 11 members from the military, intelligence services and the ministry of justice, among others - to carry out a full investigation into the alleged coup plot.

The Gambia is a largely stable country in West Africa which is popular with holidaymakers because of its beaches and wildlife.

Life has continued as normal since the government said that it had foiled a coup attempt last Tuesday.

President Barrow first took office after a shock victory over long-time ruler Yahya Jammeh in elections in 2016.

Mr Jammeh's 22-year rule was marked by state repression and human rights abuses.

He went into exile in Equatorial Guinea after his defeat, though he remains an influential figure in The Gambia.

President Barrow has been distrustful of the military, with troops from neighbouring Senegal in charge of his personal security, while the main international airport and sea port are guarded by troops from Nigeria and Ghana respectively.

This has made him unpopular with many Gambians, who feel that he has undermined the country's sovereignty by relying on foreign forces.