"In the coming days, probably tomorrow, it is possible that there will be a repatriation of illegal immigrants (to Morocco). This is an exceptional decision because it will be a first," Fernandez de la Vega, also spokeswoman for Luis Rodriguez Zapatero's Socialist government, said on Wednesday.
"In the coming days, we will work to begin reactivating the 1992 accord between Spain and Morocco on the control of migration, which has never been applied," she added in a public statement.
Her comments came as hundreds of immigrants mounted a fresh assault on Spain's north African enclave of Melilla on Wednesday, and 65 of them succeeded in breaking through its defences to what they hope would be a better life.
"Five hundred immigrants attempted to forcibly enter (Melilla)... Sixty-five managed to penetrate," Melilla police headquarters said in a statement.
In Morocco, which surrounds tiny Melilla, a source at the Interior Ministry confirmed the latest assault, but said "only a very few" people had broken through.
Recent months have seen a sharp increase of such incidents in Melilla and its twin, Ceuta, involving people from many African countries determined to escape poverty and start a new life in Europe.
"In the coming days we will work to begin reactivating the 1992 accord between Spain and Morocco on the control of migration, which has never been applied"
Maria Teresa Fernandez de la Vega,
Spanish Deputy Prime Minister
The latest assault took place in the Pinares de Rostrogordo zone where the perimeter fence has yet to be raised from three to six metres high, as is the case around the rest of the enclave, according to private Spanish radio Cadena Ser.
Medics in the zone treated many immigrants for cuts and bruises, and two were still under observation, police said, adding that two members of the Civil Guard had also been injured.
Earlier on Wednesday, Fernandez de la Vega met the Conservative local government chiefs of Melilla and Ceuta, who have strongly criticised the administration's management of the crisis.
They urged Zapatero to reaffirm Madrid's sovereignty in the two enclaves.
The latest immigrant invasion took place before dawn, the day after local Melilla government official Jose Fernandez Charcon announced that a third metal barrier would be set up to reinforce the border with Morocco.
EU justice and security commissioner Franco Frattini on Tuesday said the bloc would shortly be sending a technical mission to investigate the worsening situation on the southern coast of the Mediterranean.
Spain plans to raise the height of
the fence around Melilla
Seven African would-be immigrants have died since the beginning of the summer during similar assaults, including five in Ceuta last Thursday.
On Monday, 135 people were injured when around 650 stormed Melilla. Some 300 people broke into the same enclave in two mass stormings of the barrier, involving about 1000 people, in a similar incident.
Spain has recently been accelerating plans to raise the border fence, equipped with infrared cameras and movement detectors, while Morocco is increasing police operations in forests bordering the enclaves.
The decision, made earlier, to beef up the barriers is believed to be behind the heavy immigrant influx recently.
After Wednesday's incident, Moroccan police arrested 85 immigrants, including 13 women, bringing the total number of such arrests since the beginning of the year to 6167.