* At least 19 passengers rescued
* U.S. Coast Guard involved in search for survivors
* Authorities say smuggler vessel headed for Puerto Rico (Updates death toll, adds new details)
By Manuel Jimenez
SANTO DOMINGO, Feb 6 (Reuters) - Dominican officials were investigating the capsizing of an overloaded immigrant smuggling boat that killed 18 people and rescue teams were searching on Monday for 20 or more people missing off the Dominican Republic coast, authorities said.
A rustic vessel with about 60 people aboard left from the coast of Nagua, 130 miles (210 km) northeast of Santo Domingo, on Saturday bound for the neighboring island of Puerto Rico, and capsized in the Bay of Samana, Dominican Republic naval officials said.
Dominican authorities said 19 passengers were rescued and were admitted to a medical center with injuries.
“We are still investigating the cause of this tragedy,” said Director of Civil Defense General Luis Luna Paulino.
Five survivors were being treated on Monday and one woman was reported to be in serious condition, said local authorities.
Officials say the alarm was raised around midday on Saturday after fishermen rescued one of the vessel’s survivors.
The rescue effort continued throughout the day on Monday though hope was fading that any more survivors would be found, according to the head of the Dominican Navy, Vice-Admiral Nicolas Cabrera Arias. The captain of the capsized vessel was detained and was being questioned, he added.
Dominican Navy vessels searched the area for survivors during the weekend. The U.S. Coast Guard sent three helicopters and a cutter to the shipwreck area on Saturday at the request of Dominican authorities, Coast Guard spokesman Ricardo Castrodad said.
“They did locate a couple of bodies that were recovered by Dominican Republic authorities,” Castrodad said.
On Sunday afternoon, the Dominicans notified U.S. officials that their assistance was no longer needed.
Some of the survivors told authorities they each had paid smugglers 40,000 pesos, or about $1,000, to organize the trip.
Poor Dominicans in search of better opportunities often set out late at night on flimsy, overloaded boats, known as yolas, trying to cross the Mona Passage and reach the shores of the U.S. territory of Puerto Rico, but many die in the attempt. The treacherous 80-mile- (130-km-) wide strait is a highly used seaway that links the Caribbean Sea and the Atlantic Ocean and is notorious for dangerous tides and shallow sand banks.
“Migrants are risking their lives when they trust ruthless smugglers to make the dangerous voyage .... without any consideration to weather conditions or the safety and lives of their passengers,” said Captain Drew Pearson, U.S. Coast Guard Sector San Juan commander.
The U.S. Coast Guard intercepted 200 undocumented migrants from the Dominican Republic during the year ended on Sept. 30, and has intercepted 86 since. (Additional reporting by Jane Sutton; editing by Bill Trott and Mohammad Zargham)