* Spain's Caixabank reassures customers savings safe
* Economy minister - bank clients have nothing to fear (Adds context)
MADRID, Oct 4 (Reuters) - Spain's Caixabank, Catalonia's largest lender, and the country's economy minister reassured bank customers that their deposits are secure from a growing crisis in the region.
"Catalan banks are Spanish banks and European banks are solid and their clients have nothing to fear," Luis de Guindos, Spain's Economy Minister said after mass protests during a banned independence vote in the northeastern region.
He made those comments after Caixabank told staff in a memorandum reviewed by Reuters that they should proactively communicate to our clients "our commitment to the defense of their interests".
In the note, sent to staff late on Tuesday, the bank "reiterated that the sole objective of the entity is to protect at all times the interests of its customers, shareholders and employees, guaranteeing the integrity of deposits".
A spokesman for the bank, which has its headquarters in Barcelona, declined to comment further.
The referendum and its aftermath have plunged Spain into its worst constitutional crisis in decades, and are a political test for Prime Minister Mariano Rajoy, a conservative who has taken a hard line stance on the issue.
Spain's Banco Sabadell, the country's fifth-largest bank with a large business in Catalonia, also attempted to calm jitters.
"(Sabadell) has the mechanisms and will take the necessary measures to continue operating normally inside the Euro zone, guaranteeing the interests of its shareholders, clients and employees, in whatever scenario," Josep Oliu, its chairman, said on Tuesday.
Both banks have seen their share price fall in recent days amid the turmoil. On Wednesday, Sabadell's stock price was down almost 4 percent, while Caixabank had slipped by slightly more.
Tens of thousands of Catalans demonstrated in the streets of the northeastern region against action by the police, who tried to disrupt Sunday's vote by firing rubber bullets and charging into crowds with truncheons. The protests shut down road traffic, public transport and businesses.
Pro-independence parties who control the regional government staged Sunday's referendum in defiance of the Constitutional Court, which had ruled that the vote violated Spain's 1978 constitution which states the country is indivisible.
Catalonia, Spain's richest region, has its own language and culture and a political movement for secession that has strengthened in recent years.
Those who participated in Sunday's ballot voted overwhelmingly for independence, a result Catalan leader Carles Puigdemont said is valid and must be implemented. (Additional reporting by Sonya Dowsett and Paul Day; Writing by John O'Donnell; Editing by Keith Weir)