HAVANA (Reuters) -- Cuba, stepping up efforts to block illegal migration
                  to the United States, on Wednesday introduced tough new legislation to
                  control the building, repair and movement of small boats around its shores.

                  Details of the decree-law published in the official newspaper Granma
                  required citizens to obtain permission from port captains for practically all
                  operations or movements involving boats, including construction and
                  transport on land.

                  Offenders faced heavy fines and possible confiscation of their vessels,
                  according to Decree-Law 194 passed by Cuba's ruling Council of State on
                  Monday.

                  The tougher legislation was clearly a response to a reported increase in
                  recent months of Cubans trying to migrate illegally from their
                  communist-ruled island to the United States, either using their own boats or
                  helped by migrant smugglers operating from the United States.

                  Cuba and the United States have made public commitments to prevent such
                  attempts in line with accords they signed in 1994 and 1995 to promote safe,
                  legal and orderly migration by Cubans to the United States.

                  "Cuba has a duty to block illegal departures with all the seriousness and
                  responsibility with which we always assume our commitments," Granma
                  said.

                  It said U.S. authorities had also taken measures to halt the growing
                  clandestine transport of illegal migrants from Cuba by U.S.-based smugglers
                  using fast motor launches.

                  The latest move by Cuba's communist authorities followed a number of
                  recent dramatic incidents in which would-be Cuban migrants seeking to flee
                  the island were involved in sometimes tense confrontations with Cuban and
                  U.S. Coast Guards.

                  Earlier this month Cuban authorities blocked an attempt by a group of
                  Cubans to leave illegally in a wooden boat from the port of Puerto Padre,
                  420 miles (700 km) east of Havana.

                  The would-be migrants, who were eventually detained, had reprovisioned
                  and repaired their boat on Puerto Padre seafront watched by a large crowd
                  of supporters. The Cuban government denied U.S. news reports that a riot
                  broke out when the authorities initially tried to intervene.

                  The Cuban statement said these illegal migration attempts using small and
                  medium-sized boats "not only create disorder, threats to fishing and to
                  maritime traffic, but they also use materials and equipment obtained illicitly to
                  build or adapt vessels and use them without authorisation."

                  The new rules also penalised Cubans who used materials obtained by
                  unlawful means to build or repair boats.

                  Cuban authorities also justified the new measures as a form of clamping
                  down on illegal fishing, which they said was damaging fisheries stocks and
                  costing the island more than $20 million in lost catches each year.

                  The fines decreed in the legislation ranged from 500 Cuban pesos to 10,000
                  Cuban pesos, a small fortune in a country where the average monthly wage
                  is a little more than 200 pesos.

                  One U.S. dollar is worth 22 pesos in Cuba's authorised internal exchange
                  market.

                  In cases where the offenders were foreigners or Cubans operating in hard
                  currency, the fines would also be in hard currency, the law said.