Di EU don suspend all security cooperation with Niger after di kontri army take power in a coup.
E dey come shortly after di US declared dia "unflagging support" for ousted president Mohamed Bazoum - wey dey seen as a key Western ally for di fight against Islamist militants.
On Friday di head of di presidential guards unit Gen Abdourahmane Tchiani declare imsef Niger new leader.
E say na insecurity, economic woes and corruption lead am to seize power.
But concerns now dey for di West about which kontri di new leader go align wit.
Niger neighbours, Burkina Faso and Mali, both don pivot towards Russia since dia own coups.
EU foreign policy chief Josep Borrell bin join di US and France to refuse to recognise di coup leaders and saydem don suspend security cooperation and budgetary aid indefinitely.
Also on Saturday France, di former colonial power wey bin don move dia regional military headquarters to di konri after dem force to comot Mali, say e don suspend all development aid and budgetary support.
Meanwhile di African Union bin call on di Niger army to return to base within 15 days.
On Friday evening US Secretary of State Antony Blinken draw ears say those wey dey detain Oga Bazoum - Niger first elected leader to succeed another since independence in 1960 - say "hundreds of millions of dollars of assistance" dey at risk.
However, di leader of Russia Wagner mercenary group don reportedly describe di coup as a triumph.
"Wetin happen for Niger na nothing oda dan di struggle of di pipo of Niger with their colonisers," Yevgeny Prigozhin was quoted as saying on a Wagner-affiliated Telegram channel.
"With colonisers wey dey try to force dia rules of life on dem and dia conditions and keep dem for di state wey Africa bin dey for hundreds of years ago."
E add say: "Today dis dey effectively gain dia independence."
Di BBC never dey able to verify di authenticity of im reported comments.
Wagner dey believed to get thousands of fighters for kontris wey include di Central African Republic (CAR) and Mali, wia e get lucrative business interests but also support Russia's diplomatic and economic relations.
Wagner fighters don chop accuse of widespread human rights abuses for several African countries.
Gen Tchiani, 62, has been in charge of di presidential guard since 2011 and former President Issoufou promote am to di rank of general in 2018.
Dem don also link am to a 2015 coup attempt against di ex-president, but e bin appear for court to deny am.
On Friday Gen Tchiani tok say im junta take over sake of problems for Niger wey include insecurity, economic woes and corruption.
E also addresse Niger's global allies, say di junta go respect all of di kontri international commitments, as well as human rights.
But di junta bin don get strong words for those who oppose dem, accusing members of di ousted goment wey don run comot go foreign embassies of plotting against dem.
Dem sa any such attempt go lead to bloodshed, wey dem don avoid so far.
Life for di capital Niamey don largely go back to normal with markets and shops open, but dem bin ask civil servants to go home.
Meanwhile Nigeriens get mixed feelings about di coup, with some saying insecurity for di kontri no dey too serious enough to justify a coup. But odas don support di junta.
Niger coup na di latest in a wave of military takeovers wey don hit di West African region in recent years, toppling goments for kontri wey include Mali, Guinea and Burkina Faso.
E dey also come as a big blow to di leadership of regional body Ecowas. Just two weeks ago, di bloc chairman, President Bola Tinubu, draw ears say terrorism and di emerging pattern of coups for West Africa don reach alarming levels and demand urgent, concerted actions.
Dis na di fifth coup for Niger since e gain independence from France in 1960, on top of oda unsuccessful takeover attempts.