West African bloc ECOWAS on Wednesday expressed "deep concern" over a row between Algeria and its southern neighbour Mali.
On Monday, the two countries closed their airspace to each others' aircraft, the latest escalation in a row over accusations that Algeria shot down a Malian drone.
Read moreSahel alliance recalls ambassadors from Algiers over downed drone
In its statement, ECOWAS expressed "deep concern about the situation".
It appealed to both sides to "de-escalate the tension, foster dialogue and use regional and continental mechanisms to settle differences".
Algeria said on April 1 that it had shot down an armed reconnaissance drone in its airspace without giving further details.
Mali accused Algeria of having downed one of its drones over its territory, an allegation Algiers dismissed as false.
On Sunday, Mali and its allies Niger and Burkina Faso – all three countries run by the military – withdrew their ambassadors from Algeria, a move Algiers quickly reciprocated.
The airspace closures followed a day later.
Mali's ruling junta also pulled out of the Sahel region's joint military staff committee, known by its French acronym CEMOC.
CEMOC was formed by Algeria, Mali, Niger and Mauritania in April 2010 to coordinate their efforts against al Qaeda's north African affiliate AQIM.
Niger, Burkina Faso and Mali have since formed their own confederation, the Alliance of Sahel States (AES), set up initially as a defence pact in 2023.
On Tuesday, around a hundred youths demonstrated in front of the Algeria embassy in Bamako, protesting against Algeria.
Relations between the two countries have got steadily worse in recent years. Their respective ambassadors were also recalled in December 2023 for several weeks.
Northern Mali borders Algeria and is the battleground in a separatist rebellion, while jihadist attacks also trouble the nation.
(FRANCE 24 with AFP)