HAVANA - Visiting former US President Jimmy Carter said on Tuesday that he hoped he would be able to help improve troubled relations between Cuba and the United States.

Carter, who is on a formal visit to the Caribbean island state, told reporters he had talked with Cuban authorities about the case of jailed US citizen Alan Gross.

Gross was sentenced to 15 years in prison earlier this month for "acts against the independence or territorial integrity of the state."

Carter said the main purpose of his visit was to boost bilateral relations and visit social projects, but not to try to convince Cuban authorities to allow him to take Gross home with him.

Gross, a 61-year-old telecommunication technician working for a company subcontracted by the US State Department, was arrested when distributing satellite communications devices. He had been accused of spying, but Washington denies the charges.

Carter Tuesday also visited a convent where Cuban authorities are developing a social program involving hundreds of volunteers. He is scheduled to meet Cuban leader Raul Castro.

Carter visited the island in 2002 and set up a number of social development programs under his Carter Center foundation.