President Bush has ordered that U.S. nationals be barred from sending money to Cuba through the transfer company SerCuba.

BY PABLO BACHELET

WASHINGTON - The Bush administration announced Monday that it was barring U.S. nationals from using SerCuba, a money-transfer company, to send remittances to the island.

The Treasury Department added SerCuba to its list of Specially Designated Nationals, meaning that U.S. citizens and residents are forbidden from engaging in any transactions with the firm and that any assets belonging to the firm in the hands of U.S. nationals would be blocked.

SerCuba, Treasury said in a statement, operates under Cuban law and is supported by Cimex, a state-run trading company.

SerCuba allows people subject to U.S. jurisdiction to send cash to Cuba via third countries or through its website ( www.sercu ba.com), according to the Bush administration.

''Today, we are financially isolating SerCuba to make it more difficult for the Cuban regime to obtain the hard currency it uses to oppress its own people and to prop up its government,'' said Juan Carlos Zarate, the Treasury's assistant secretary for Terrorist Financing and Financial Crime.

Treasury officials, however, declined to say whether Cuban Americans had used SerCuba to transfer funds.

SerCuba was launched in August by the Cuban Telecommunications Company (ETECSA), just weeks after the Bush administration announced rules aimed at toughening the embargo against the island and hastening the fall of the Fidel Castro government. Anyone found guilty of doing business with SerCuba is subject to criminal prosecution and fines, Treasury Department officials said.

SerCuba allows the island's residents to use a debit card on the remittances they receive from Italy and Spain, the two countries where SerCuba operates outside of Cuba. The debit card is free, and senders pay a transfer fee that starts at 13 euros or $16.50. Europe's Telecom Italia holds a 27 percent stake in ETECSA.

Institutions like the Inter-American Development Bank (IDB) have promoted the use of debit cards as a way to help lower the cost of sending remittances, which tends to benefit the poorer segments of societies. The average cost of sending remittances to Cuba is 12 percent of the money sent, according to a May 2004 IDB study, the highest rate in Latin America.

Remittances are a vital source of income for the island, with yearly estimates varying from $800 million to $1.2 billion, most of it coming from about 1.3 million Cubans in the United States.

The Bush administration says much of that money ends up in state coffers and is used to repress the Cuban people, but it has stopped short of banning remittances outright.

At the end of June, however, it limited the beneficiaries of remittances to immediate family members and forbid sending money to the Cuban Communist Party members.

Saúl González, a spokesman for ETECSA, said SerCuba ws ``a private company that is independent of any government.''

Sercuba operates a call center in Havana, 16 offices in Cuba and one each in Italy and Spain.