Since 2014, tens of thousands of West and Central Africans have been refused entry into Algeria a which has become a transit point for migrants to reach mainland Europe via the Mediterranean Sea.
Migrants refused entry are generally abandoned in the middle of the desert along Niger's border.
"Large-scale police raids are regularly carried out in some central districts in the town of Tamanrasset (southern Algeria) where sub-Saharan nationals live, including many Nigeriens," Niamey said in the statement.
Algiers has "in recent days increased" repatriation and refoulement operations of sub-Saharan migrants, it said.
The statement cited witnesses who report that during these operations places lived in by migrants, "mostly Nigeriens" were "ransacked by Algerian police units who seize all valuable objects they find on the premises."
It was "in view of the gravity of this situation" that the Niger foreign ministry "decided to summon the Algerian ambassador Bekhedda Mehdi, on April 3," Niamey said.
The deputy secretary general of Niger's foreign ministry, Oumar Ibrahim Sidi, who received the Algerian diplomat, said the entire government was "against the violent nature of the modus operandi used by Algerian security forces to carry out these operations."
Sidi asked Mehdi to intervene with the Algerian authorities so that the refoulement operations take place "with respect for the dignity of physical and moral integrity."
NGOs, including Medecins sans frontieres (Doctors Without Borders), have previously denounced "the inhumane treatment" inflicted on West African migrants seeking to reach Europe — with an average of about 2,000 being refused entry every month into Algeria and Libya.
Algiers has denied these accusations, labeling them "malicious."