BY NANCY SAN MARTIN

U.S. officials said harsher Cuban sanctions that have angered those on and off the island are intended only to hurt Castro.

Tightened restrictions on Cuba travel, remittances and gift parcels taking effect today mark the start of a ''comprehensive, integrated strategy'' intended to hurt Fidel Castro's government, not Cubans or Cuban Americans, U.S. authorities say.

''These are specific steps to signal to the regime that they cannot simply hold on,'' said a senior State Department official, who spoke on condition of anonymity. ``It's a sign of disapproval of the [Cuban] government's current and past behavior and to show that the behavior has consequences.''

The new rules, which have caused panic among Cubans on and off the island and spurred criticism against the Bush administration, are only a small component of some 650 recommendations contained in a report by the Commission for Assistance to a Free Cuba to hasten a democratic transition.

ACTS OF AGGRESSION

The Cuban government has portrayed the measures as acts of U.S. aggression and responded by increasing prices at dollar stores, organizing a massive protest outside the U.S. Interests Section and hinting that harder times on the island could provoke another mass exodus.

Future initiatives include the appointment of a transition coordinator to implement the new measures and identification of resources for $45 million to be spent over the next two years, including the purchase of an airplane and broadcasting equipment to break through Cuba's jamming of Radio and TV Martí.

Several analysts said the effort is unprecedented and comparable to strategies used during the Cold War.

''All those things have been done and had relative success in undermining the communist regime in Eastern Europe,'' said Jaime Suchlicki, director of the University of Miami's Institute for Cuban and Cuban-American Studies. ``This was not an overnight operation. It took years.''

HITTING THE ECONOMY

The recommendations came after months of intelligence gathering, analysis and debate over how to hit the Castro government where it is most vulnerable: its pocket.

In 2003, an estimated 176,000 U.S. residents legally traveled to Cuba, spending about $200 million, according to the U.S.-Cuba Trade and Economic Council, which monitors Cuba's economy. The overwhelming majority -- about 128,000 -- claimed to be visiting family.

The Bush administration wanted to drastically reduce the amount of money carried by those visitors and do away with extra dollars that come from airport fees charged by the Cuban government. So the visits are now restricted to once every three years.

Remittances also were limited because only a small percentage of the population was found to be direct beneficiaries of the cash transfers from American relatives. According to the Cuban government's own estimates, about 30 percent of its 11 million citizens have direct access to hard currency, either through remittances or dollar-related jobs.

The removal of clothing and personal hygiene products from gift parcels came as a result of abuses in bulk packages appeared to support businesses instead of relatives.