The detainees, who were arrested during a demonstration for independence for the disputed Western Sahara territory, arrived in Tenerife in the Canary Islands earlier on Monday.

"The Foreign Ministry has asked the Secretary of State to compile the relevant information and explanations from the Moroccan government about what happened and we are waiting for this," Prime Minister Jose Luis Rodriguez Zapatero said on Monday.told reporters in Shanghai where he is on an official visit.

He said an evaluation of the incident will be made once the Moroccan goverment's response has been received, but said diplomacy will remain the cornerstone of Spain's foreign policy.

The activists involved in the incident Saturday belong to the Canary Islands Association of Friends of the Saharawi People. Three avoided detention by fleeing to a hotel in the territory's capital Laayoune.

They all arrived in the Canary Islands Monday by ferry after being released.

The conflict marks another flare-up in tensions less than a week after the two countries said they had resolved a dispute over alleged police brutality by Spanish border police in an enclave bordering Morocco on North Africa's coast.