Tension has remained high in Niger Republic as the military junta refused entry to a negotiating mission planned for Tuesday by the United Nations, African Union (AU) and Economic Community of West African States (ECOWAS).

U.S. diplomat Victoria Nuland spoke with members of the junta in the capital, Niamey, on Monday, but was not allowed to meet either the detained President Mohamed Bazoum or the military ruler General Abdourahamane Tchiani.

However, the U.S. government said it would continue to hope for a diplomatic solution, State Department spokesman, Matthew Miller, said on Tuesday.

Meanwhile, the military governments of Burkina Faso and Mali have called on the UN Security Council not to allow military action against the putschists in Niger.

ECOWAS had threatened a possible military action against the junta who seized power in Niger, suspended the constitution, and imprisoned the president.

Burkinese Foreign Minister Olivia Rouamba and his Malian counterpart, Abdoulaye Diop in a letter addressed to the UN Security Council and the African Union urged them “to prevent, by all means at its disposal, armed action against a sovereign state, the consequences of which would be unforeseeable in their magnitude.”

Both countries said the aim was “to avoid the deterioration of the security situation with the multiplication and spread of terrorists’ groups and a humanitarian tragedy.

Burkina Faso and Mali are currently suspended from ECOWAS following coups and have clearly shown support for the military rulers in Niger.

They declared that they would not support the ECOWAS sanctions and that any military action would be seen as a “declaration of war” against their own states.