The bodies of 11 missing Niger soldiers have been discovered after an ambush by armed men killed 17 of their colleagues on patrol near the Mali border, security sources said.
"We have confirmation that the dead bodies of the eleven missing soldiers have been found, bringing the death toll to 28," a source said late Wednesday.
The military patrol was ambushed on Tuesday near the village of Tongo Tongo in the western Tillaberi region, sources said.
One of the military vehicles had set off an explosive device.
A source referred to what happened as a "terrorist attack".
Several troops were also injured and evacuated to the capital Niamey, a different source told AFP.
According to the news site Actuniger, a patrol of 52 Niger soldiers happened upon a group of heavily armed men at Baley Beri, near Tongo Tongo. Heavy fighting ensued, lasting more than two hours.
Twenty-two soldiers made it back to their base at Ouallam in three vehicles, while the rest were unaccounted for, it said, citing local and security sources.
This is the same region where four American and five Niger soldiers were killed in a jihadist attack in October 2017.
Niger is one of a number of poor, fragile countries in the Sahel region that have been hit by a jihadist revolt.
Different jihadist groups operate in the country's west and north, and Boko Haram from Nigeria in its southeast.
The country is part of the so-called G5 Sahel group set up to manage a coordinated response to the jihadist insurgency.