By David Adams

MIAMI (Reuters) - Cuba is shutting down nearly all of its consular services in the United States "until further notice" after it said it was unable to find a bank willing to handle its business, the government announced on Tuesday, blaming the situation on the longstanding U.S. economic embargo.

The decision threatens to disrupt a recent surge in travel between the United States and Cuba on the eve of the upcoming busy holiday season.

The Cuban Interests Section, Havana's diplomatic mission in Washington, said in a news release that it was informed in July by its bank, M&T Bank, that it would no longer be able to provide banking services to foreign missions.

Officials at Buffalo, New York-based M&T Bank did not respond to phone calls seeking comment. The Obama administration did not immediately comment on the announcement.

Due to the U.S. embargo, "and despite the numerous efforts made with the Department of State," Cuba was unable to find a U.S. or international bank to operate its U.S. accounts, the Cuban Interests Section in Washington said in Tuesday's news release.

The decision came as a shock to travel companies offering services to Cuba, saying it would affect many travelers, both Cuban and American, who need documents approved by Cuban consular officials prior to departure.

"I really don't know how it's going to work out. We don't have much information yet," said Tessie Aral, president of Miami-based ABC Charters, one of several companies offering charter flights to various cities in Cuba.

Christmas period flights were sold out between December 20 and December 31 and those passengers would not be affected as they already have travel documents, she said.

But other travelers who do not have up-to-date Cuban passports "would have a problem," she said.

SPECIAL CASES

Cuba said the loss of banking services meant consular services would only be available for humanitarian and special cases "until further notice."

Story continues

Cuba said it "particularly regrets the effects this may have on Cuban and U.S. citizens ... with the negative impact on family visits, academic, cultural, educational, scientific, sports and other kind of exchange between Cuba and the United States."

While the Cuban government does not publish statistics on the number of Cuban Americans visiting the country each year, tourism industry sources and U.S. charter companies and travel agencies place the figure at around 350,000, many of whom must seek entry visas if they do not have a valid Cuban passport.

Cuban emigres who lack U.S. citizenship must keep their Cuban passports up to date through the Cuban Interests Section in Washington.

Close to 100,000 Americans also visited Cuba in 2012, according to the Cuban government, under the Obama administration's people-to-people policy, providing much needed revenues to the hotel and restaurant industries.

Cuban Americans usually stay with family and friends when visiting home. Nevertheless, they spend hundreds of millions of dollars annually renting cars, treating their families and friends to meals at restaurants and purchasing goods at state stores, creating revenue badly needed by the cash-strapped Cuban government.

Cuba said the United States was required under the diplomatic treaties to ensure "full facilities for the performance of the functions" of its diplomatic missions and consular offices in the United States.

The U.S. does facilitate connections but has no ability to compel private banks to provide services, according to a senior U.S. official.

(Additional reporting by Marc Frank in Havana; Editing by Vicki Allen)