Diplomats from the African Union, the UN and the Economic Community of West African States (ECOWAS) were due to arrive in the capital Niamey on Wednesday.
“The current context of anger and revolt among the population following the sanctions imposed by ECOWAS makes it impossible to welcome this delegation in the required serenity and security,” said the letter addressed to the ECOWAS representation in Niamey.
In the aftermath of the July 26 military coup, ECOWAS ordered the junta to reinstate deposed President Mohamed Bazoum within one week or face possible military intervention to restore constitutional order.
But on Sunday, the junta responded by closing the country’s airspace as the deadline expired.
The bloc’s leaders are scheduled to meet again on Thursday in Nigeria to consider and discuss the political crisis and recent developments in Niger.
New sanctions announced
Meanwhile, ECOWAS chairman and Nigeria's President Bola Ahmed Tinubu ordered new sanctions against the junta on Tuesday, hours after the military leaders blocked the latest diplomatic efforts.
Tinubu imposed the sanctions through Nigeria's central bank, targeting entities and individuals involved in the coup, presidential spokesperson Ajuri Ngelale told reporters in Abuja.
Last week, an ECOWAS mission led by Abdulsalami Abubakar, a former military ruler of Nigeria, visited Niamey. But Gen. Abdourahamane Tchiani, the former commander of Niger's presidential guard, who declared himself the head of a transitional government, refused to see them.
Tchiani also refused to meet with US Acting Deputy Secretary of State Victoria Nuland, who was in Niamey on Monday. Nuland, who said her talks with junior officers were “frank and difficult,” was also denied the opportunity to meet with Bazoum, who is reportedly being held hostage.
But on the same day, Tchiani was reported to have met with a joint delegation from neighboring Mali and Burkina Faso, which have declared their strong backing for the coup leaders.