Algeria recalled its ambassador from Madrid on Saturday in protest against Spain's decision to back a Moroccan autonomy plan for the Sahara region.
An Algerian Foreign Ministry statement condemned the "abrupt about-turn" by Madrid, which had previously maintained neutrality in the decades-old conflict for the territory between Morocco and the Algerian-backed Polisario Front independence movement.
Spanish Foreign Minister Jose Manuel Albares, speaking on Friday, backed a 2007 proposal by Morocco to offer Sahara autonomy under its sovereignty, describing it as the "most serious, realistic and credible basis" to end the long-running conflict.
"Completely stunned by the statements on the Sahara issue from the highest levels of the Spanish government, and surprised by this abrupt about-turn from Sahara's former rulers, the Algerian authorities have decided to recall the ambassador to Madrid for consultations with immediate effect," the ministry said.
The Polisario had already responded angrily to the statement from Mr Albares, calling for political pressure to be put on Madrid for a change of heart.
The movement still insists on the full application of a ceasefire agreement brokered by the United Nations in 1991, which provided for a UN-supervised referendum on independence for the territory.
Spain has maintained generally good relations with Algeria and last year imported more than 40 per cent of its gas from the North African country, which recently offered its bountiful supply to the EU to ease the current shortage.
Its ties with Morocco have been more problematic.
A decision in April 2021 to allow Polisario leader Brahim Ghali to receive medical treatment at a Spanish hospital drew a furious response from Rabat.
The following month, hundreds of would-be Moroccan migrants stormed the border around the Spanish north African exclave of Ceuta, taking advantage of the withdrawal of Moroccan border guards to penetrate the remote outpost of the EU.
Rabat quickly welcomed Madrid's change of policy, describing it as "constructive".
Bernabe Lopez, professor of Arab and Islamic studies at the Autonomous University of Madrid, said the migrant issue was the main spur for Spain's move.
Madrid wanted to see Moroccan border guards exercise "more control and not this deliberate lack of control", Mr Lopez said.
The US this month reiterated its support for Morocco's autonomy offer.
"We continue to view Morocco's autonomy plan as serious, credible and realistic," Deputy Secretary of State Wendy Sherman said on a visit to Rabat.
In late 2020, the administration of then-president Donald Trump recognised Moroccan sovereignty over the Sahara as a quid pro quo for the kingdom mending ties with Israel. The deal sparked renewed tension with Algeria.
President Joe Biden's administration has not reversed Mr Trump's decision.
