Volkswacht Bodensee - Thousands of coup supporters rally near French base in Niger

Fears also mounted for elected President Mohamed Bazoum, who was ousted by members of his guard on July 26, with reports saying his detention conditions were deteriorating.

Protesters near the base on the outskirts of the capital Niamey shouted "down with France, down with ECOWAS", a reference to the West African bloc which on Thursday approved deployment of a "standby force to restore constitutional order".

Many brandished Russian and Niger flags and yelled their support for the country's new strongman, General Abdourahamane Tiani.

"We are going to make the French leave! ECOWAS isn't independent, it's being manipulated by France," said one demonstrator, Aziz Rabeh Ali, a member of a students' union.

Former colonial power France has around 1,500 personnel in Niger as part of a force battling an eight-year-old jihadist insurgency.

It is facing growing hostility across the Sahel, withdrawing its anti-jihadist forces from neighbouring Mali and Burkina Faso last year after falling out with military governments that ousted elected leaders.

Niger's new leaders scrapped defence agreements with France last week, while a hostile protest outside the French embassy in Niamey on July 30 prompted Paris to evacuate its citizens.

- Fears for Bazoum -

The European Union and African Union joined others in sounding the alarm for Bazoum on Friday.

"Bazoum and his family, according to the latest information, have been deprived of food, electricity and medical care for several days," said EU foreign policy chief Josep Borrell.

UN rights chief Volker Turk said Bazoum's reported detention conditions "could amount to inhuman and degrading treatment, in violation of international human rights law."

The AU echoed the concern, saying "such treatment of a democratically elected president" was "unacceptable".

German Foreign Minister Annalena Baerbock warned that the "coup plotters must face harsh consequences should anything happen" to Bazoum or his family.

A source close to Bazoum said "he's OK, but the conditions are very difficult," adding that the coup leaders had brandished the threat of assaulting him in the event of military intervention.

Human Rights Watch (HRW) said it had spoken to Bazoum earlier this week. The 63-year-old described the treatment of him, his wife and their 20-year-old son as "inhuman and cruel", HRW said.

"I'm not allowed to receive my family members (or) my friends who have been bringing food and other supplies to us," the group quoted him as saying.

"My son is sick, has a serious heart condition, and needs to see a doctor," he was quoted as saying. "They've refused to let him get medical treatment."

- Intervention warning -

The Economic Community of West African States (ECOWAS) on Thursday approved the deployment of what it called a "standby force to restore constitutional order" in Niger following an emergency summit in the Nigerian capital Abuja.

Chiefs of staff from ECOWAS members will meet on Saturday in Ghana's capital Accra, regional military sources said on Friday.

The leaders did not provide any details on the force or any timetable for action, and emphasised they still wanted a peaceful solution.

Under pressure to stem a cascade of coups among its members, ECOWAS had previously issued a seven-day ultimatum to the coup leaders to return Bazoum to power.

But the regime defied the deadline, which expired on Sunday without any action being taken.

- Troubled region -

Since 1990, the 15-country bloc has intervened among six of its members at times of civil war, insurrection or political turmoil.

But the possibility of intervention in deeply fragile Niger has sparked debate within its ranks and warnings from neighbouring Algeria as well as Russia.

Moscow on Friday said a military solution "could lead to a protracted confrontation" in Niger and "a sharp destabilisation" across the Sahel.

Military-ruled ECOWAS members Mali and Burkina Faso have warned an intervention would be a "declaration of war" on their countries.

Countries in the arid western Sahel region are among the world's poorest and most turbulent nations.

The latest coup is Niger's fifth since the landlocked country gained independence from France in 1960.

Like Mali and Burkina Faso, the country is struggling with a brutal jihadist insurgency that has claimed thousands of lives, forced many people from their homes and undermined faith in government.

C.Kovalenko--BTB