Supporters of a coup in Niger have attacked the headquarters of the ousted president's party, setting it on fire and stoning and burning cars outside.

The small group of arsonists had broken away from a larger show of support for the coup leaders outside parliament, where Russian flags were on show.

The army has now given its backing to the troops who took President Mohamed Bazoum captive on Wednesday.

Russia joined other countries and the UN in calling for Mr Bazoum's release.

The 64-year-old, who was elected as Niger's president two years ago, is a key Western ally in the fight against Islamist militants in West Africa.

The US and France, the former colonial power, both have military bases in the uranium-rich country - and have condemned the coup.

US Secretary of State Antony Blinken called up Mr Bazoum promising Washington's "unwavering support".

Mr Bazoum took to Twitter on Thursday morning to issue a defiant statement: "The hard-won achievements will be safeguarded. All Nigeriens who love democracy and freedom will see to it."

His foreign minister has also been trying to rally support and urge dialogue, but the army chief of staff said he was backing the takeover to avoid fighting within the armed forces.

It remains unclear who is really in charge of Niger as the junta has not announced its leader.

State TV has been repeating the late-night coup announcement interspersed with patriot music and Quranic verses - and its usual lunchtime news bulletin was not aired.

But in the capital, Niamey, shops and markets opened for business and after delays due to heavy rain early in the morning, coup supporters took to the streets.

The hundreds who gathered outside the National Assembly had some Russian flags, while others held up hand-written signs saying: "Down with France" and "Foreign bases out".

Russian Foreign Minister Sergei Lavrov said constitutional order in Niger should be restored, Reuters says, quoting Russia's state-owned Tass news agency.

Some civil society groups in Niger have been calling for a move away from France and towards Russia in recent weeks.

The junta has reprimanded France for violating the closure of the country's borders after a military plane landed at an air-force base on Thursday morning. (BBC)

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