VALENCIA, Spain (Reuters) - A naval convoy carrying 629 rescued migrants will arrive in the Spanish port of Valencia on Sunday, putting an end to their grueling nine days at sea but leaving wide open a fierce debate in Europe over how to handle immigration.

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Spain swooped to help the group of mainly sub-Saharan Africans on board the Aquarius last week, offering the charity-run ship a berth 700 nautical miles away after Italy and Malta refused to let it dock.

After Italy’s new government used the ship to assert its anti-immigrant credentials, Spanish Prime Minister Pedro Sanchez, in office for just over a week, took an opportunity to underline a more liberal stance.

But the plight of the Aquarius has highlighted the European Union’s failure to agree on how to manage huge numbers of people fleeing poverty and conflict.

“People are coming to Europe seeking European values, of solidarity and support,” Red Cross Secretary General Elhadj As Sy told a news conference in Valencia on Saturday.

“Anything less than that is a betrayal (of) Europe itself.”

A staff of 2,320, including volunteers, translators, police and health officials are awaiting the Aquarius and two Italian vessels that shared its passengers to make the voyage safer.

As soon as the boats arrive, the seven pregnant women on board will be immediately brought to land for check-ups, and everyone on board, including 123 minors, will be given psychological attention, Spanish Red Cross officials said.

Anti-migrant feeling has surged in Italy as more than 600,000 people have arrived on its shores over the past five years, helping to propel the nationalist League into a coalition government.

Far fewer come to Spain, but the numbers are rising fast.

Most Spaniards support the idea of welcoming and helping to integrate refugees, pollsters say, allowing Sanchez, a Socialist, to offer migrant-friendly policies to voters who feel previous governments did not do enough.

France, which chided Italy for turning away the Aquarius, has offered to take in any passengers who qualify for asylum and want to go there.