"The land and air borders with Algeria, Burkina Faso, Libya, Mali and Chad are reopened" from "today", he declared, hours after a first French evacuation flight took off and five days before a deadline to restore constitutional order issued by a bloc of West African countries.

The first planes carrying French and other European citizens evacuated from Niger landed in Paris Wednesday, a week after a coup toppled one of the last pro-Western leaders in the jihadist-plagued Sahel.

President Mohamed Bazoum was detained by his own presidential guard in a third coup in three years in the Sahel, following putsches in neighbouring Mali and Burkina Faso, also former French colonies.

West African leaders have threatened to use force to reinstate the democratically elected Bazoum and slapped financial sanctions on the junta.

The military chiefs for nations in the key regional bloc ECOWAS will meet in the Nigerian capital Abuja from Wednesday to Friday to discuss the overthrow.

After anti-French protests unleashed by the coup, Paris on Tuesday said it would withdraw its nationals from the capital Niamey.

The United States is not joining European allies in evacuating its citizens from Niger for now, but has suspended activities such as training with Niamey's forces, officials said Tuesday.

Washington is "certainly aware of efforts by France and other European nations to evacuate their citizens. At the same time, we don't have any indications of direct threats to US citizens or to our facilities, so we have not changed our posture with respect to our presence in Niger at this time," National Security Council spokesman John Kirby said.

About 1,000 US troops are stationed in the land-locked African nation, where they were helping the ousted president, Mohamed Bazoum, combat a regional Islamist insurgency.

Kirby said the White House still sees a "window" for diplomacy to resolve the Niger crisis but added that "we're monitoring it literally by the hour."