SANTO DOMINGO, Dominican Republic -- In the wake of reported plots to kill Fidel Castro during a Caribbean summit here, Dominican officials Wednesday expelled a Cuban exile who is from Miami and paid special attention to others arriving.

Local radio and television have carried several reports of ultra-tight security because of published reports about exile plots to kill the Cuban president during the summit, which begins today.

Immigration officials at Santo Domingo's international airport were seen checking the names of Cuban-born arrivals against a one-page typed list of exiles considered worthy of special monitoring.

One Miami exile on the list, Fernando Canto, flew back to South Florida Wednesday after Dominican officials refused him permission to stay longer in La Romana, a resort town east of Santo Domingo.

Canto charged that two Havana security agents and a Dominican police lieutenant had interrogated him for 2 1/2 hours this weekend when he flew from Miami to La Romana to visit a factory he owns there.

He was eventually allowed to enter the country but was ordered to leave by Wednesday even though he is a legal resident of the Dominican Republic because of his businesses here, Canto told reporters Wednesday in La Romana.

Contacted before the Canto case became known, the head of the country's FBI confirmed that security agents at airports have a list of exile ``activists in the anti-Castro cause'' but said no one would be blocked from entering.

``This is simply vigilance. No one has been turned back, and no one has been arrested. But it is logical that we take precautions and monitor some people,'' said Gen. Sigfrido Pared Perez, head of the National Investigations Directorate.

Dominican radio reported that two Cuban airplanes landed Wednesday carrying several bomb-sniffing dogs and about 100 Cuban security agents, and metal detectors were deployed at the seaside hotel where the summit will be held.

But security at the airport appeared only slightly less lax than usual, with inspectors barely touching the suitcases of two Cuban Americans who arrived Tuesday.

Castro and 16 other Caribbean heads of government will meet today through Saturday to discuss a number of regional issues, but the Cuban president is expected to stay on another two days.

The Herald reported on Aug. 9 that Luis Posada Carriles, a Cuban exile implicated in several terror attacks, and three Miami exiles were plotting to assassinate Castro during the summit. And last month, the U.S. Embassy in the Santo Domingo warned of possible terrorist threats to airliners flying between the Dominican Republic and Cuba.

Pro- and anti-Castro groups that have been girding for weeks for Castro's first visit to the Dominican Republic clashed Wednesday in a brief melee while several policemen stood nearby. Members of the minuscule Force of the Revolution, a communist party, attacked a group of Cuban exiles who tried to talk to the media in downtown Santo Domingo.

Force members also plastered posters of Castro for several blocks around the Jaragua hotel, where Castro and the other leaders will stay and meet.

``Leader of America, welcome to the Dominican Republic,'' say some of the posters.

Meanwhile, Cuban exiles living here have been holding news conferences and sending faxes to reporters saying that Cubans lack the freedoms that Dominicans enjoy -- a free press and a multiparty democracy among them.

``We want to show Dominicans who don't understand that he is the problem,'' said Mario Rivadulla, journalist and former president of the Association of Cubans in the Dominican Republic.

But the bulk of the people preparing for Castro's visit in fact were Ministry of Public Works crews ordered to tidy up the capital city of Santo Domingo and the towns that Castro will visit after the summit.

Workers have trimmed trees, filled potholes, replaced burned-out street and traffic lights and picked up some of the garbage along the route from the airport to the Jaragua Hotel.

Dominican newspapers reported the crews also gave a new coat of paint to a house in the northwest coastal city of Montecristi where Jose Marti, hero of the Cuban war of independence from Spain, stayed in 1895.

Castro is expected to visit Montecristi and Bani, a town 40 miles west of Santo Domingo, after the summit ends, although his exact schedule is being kept secret for security reasons.