Algeria said on Thursday it was imposing visa requirement on Moroccans.
A statement carried by Algeria's official APS news agency charged that Morocco had "engaged in various actions that threaten Algeria's stability."
Earlier this month, authorities in the Algerian city of Tlemcen said they had arrested seven people, including four Moroccans, accused of belonging to a spy ring.
Algiers broke diplomatic ties with Rabat in August 2021, citing "hostile acts" by its neighbour, months after Morocco normalised relations with Israel.
Border closed for three decades
Morocco described the 2021 decision to break off diplomatic relations as "completely unjustified."
The border between Algeria and Morocco has been closed for 30 years.
But travellers from Morocco did not need a visa to enter Algerian territory – despite the lack of direct flights – and neither do Algerians to enter Morocco.
There was no immediate response from Rabat to Thursday's move by Algiers. Algeria said it was "committed to preserving ties" with the "brotherly" Moroccan people, and blamed the Rabat authorities for recent diplomatic rifts.
'Bears responsibility'
"The Moroccan regime alone bears responsibility for the current deterioration of bilateral relations due to its hostile and aggressive actions against Algeria," it said.
The two countries remain at odds over the Western Sahara.
The United Nations, which has had a peacekeeping mission in Western Sahara since 1991, regards it as a "non-self-governing territory."
After French President Emmanuel Macron said in July that "the only solution" was a Moroccan plan to grant the territory autonomy within the kingdom without the option of independence, Algeria recalled its ambassador.
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