(AP Photo/Adalberto Roque, Pool)

WASHINGTON - Piece by piece, in backpacks and carry-on bags, American aid contractor Alan Gross made sure laptops, smartphones, hard drives and networking equipment were secreted into Cuba. The most sensitive item, according to official trip reports, was the last one: a specialized mobile phone chip that experts say is often used by the Pentagon and the CIA to make satellite signals virtually impossible to track.

The purpose, according to an Associated Press review of Gross' reports, was to set up uncensored satellite Internet service for Cuba's small Jewish community.

The operation was funded as democracy promotion for the U.S. Agency for International Development, established in 1961 to provide economic, development and humanitarian assistance around the world in support of U.S. foreign policy goals. Gross, however, identified himself as a member of a Jewish humanitarian group, not a representative of the U.S. government.

Cuban President Raul Castro called him a spy, and Gross was sentenced last March to 15 years in prison for seeking to "undermine the integrity and independence" of Cuba. U.S. officials say he did nothing wrong and was just carrying out the normal mission of USAID.

Gross said at his trial in Cuba that he was a "trusting fool" who was duped. But his trip reports indicate that he knew his activities were illegal in Cuba and that he worried about the danger, including possible expulsion.

One report says a community leader "made it abundantly clear that we are all 'playing with fire.'"

Another time Gross said: "This is very risky business in no uncertain terms."

And finally: "Detection of satellite signals will be catastrophic."

The case has heightened frictions in the decades-long political struggle between the United States and its communist neighbour to the south, and raises questions about how far democracy-building programs have gone - and whether cloak-and-dagger work is better left to intelligence operatives.

Gross' company, JBDC Inc., which specializes in setting up Internet access in remote locations like Iraq and Afghanistan, had been hired by Development Alternatives Inc., or DAI, of Bethesda, Maryland, which had a multimillion-dollar contract with USAID to break Cuba's information blockade by "technological outreach through phone banks, satellite Internet and cellphones."

USAID officials reviewed Gross' trip reports and received regular briefings on his progress, according to DAI spokesman Steven O'Connor. The reports were made available to the AP by a person familiar with the case who insisted on anonymity because of the documents' sensitivity.

The reports cover four visits over a five-month period in 2009. Another report, written by a representative of Gross' company, covered his fifth and final trip, the one that ended with his arrest on Dec. 3, 2009.

Together, the reports detail the lengths to which Gross went to escape Cuban authorities' detection.

To avoid airport scrutiny, Gross enlisted the help of other American Jews to bring in electronic equipment a piece at a time. He instructed his helpers to pack items, some of them banned in Cuba, in carry-on luggage, not checked bags.

He once drove seven hours after clearing security and customs rather than risk airport searches.

On his final trip, he brought in a "discreet" SIM card - or subscriber identity module card - intended to keep satellite phone transmissions from being pinpointed within 250 miles (400 kilometres), if they were detected at all.

The type of SIM card used by Gross is not available on the open market and is distributed only to governments, according to an official at a satellite telephone company familiar with the technology and a former U.S. intelligence official who has used such a chip. The officials, who spoke on condition of anonymity because of the sensitivity of the technology, said the chips are provided most frequently to the Defence Department and the CIA, but also can be obtained by the State Department, which oversees USAID.

Asked how Gross obtained the card, USAID spokesman Drew Bailey said only that the agency played no role in helping Gross acquire equipment. "We are a development agency, not an intelligence agency," he said.

Cuba's communist government considers all USAID democracy promotion activities to be illegal and a national security threat. USAID denies that any of its work is covert.

Gross' American lawyer, Peter J. Kahn, declined comment but has said in the past that Gross' actions were not aimed at subverting the Cuban government.

Cuban authorities consider Internet access to be a matter of national security and block some sites that are critical of the government, as well as pages with content that they deem as counterrevolutionary. Most Cubans have access only to a severely restricted island-wide Intranet service.

Proponents of providing Internet access say it can undermine authoritarian governments that control the flow of information to their people. Critics say the practice not only endangers contractors like Gross, but all American aid workers, even those not involved in secret activities.

"All too often, the outside perception is that these USAID people are intelligence officers," said Philip Giraldi, an ex-CIA officer. "That makes it bad for USAID, it makes it bad for the CIA and for any other intelligence agency who like to fly underneath the radar."

Even before he delivered the special SIM card, Gross noted in a trip report that use of Internet satellite phones would be "problematic if exposed." He was aware that authorities were using sophisticated detection equipment and said he saw workers for the government-owned telecommunications service provider conduct a radio frequency "sniff" the day before he was to set up a community's Wi-Fi operation.