MIAMI (AP) _ A Cuban rescued at sea by the Coast Guard turned out to be wanted on charges of hijacking a flight to Havana soon after he first came to this country in the 1980 Mariel boatlift, authorities said Wednesday.

Elvis Rafael Fonseca Machado, 46, was ordered held Wednesday in Key West on $1 million bond, said Paul Miller, an FBI spokesman in Miami. Fonseca will get a hearing to determine if he should be sent to Puerto Rico, where the federal air-piracy charges were filed.

Fonseca was among six Cubans the Coast Guard picked up from two rafts Tuesday about 50 miles south of Key West.

The rafters are part of a steady stream of Cubans fleeing the island nation by boat. The Coast Guard has picked up 988 people so far this year, including 119 during June. A total of 2,557 were rescued during 1992.

The six Cubans were turned over to the Immigration and Naturalization Service for routine questioning and Fonseca admitted his identity, Miller said.

Fonseca and Jose Garcia Sanchez were accused of boarding National Flight 872, carrying 12 crew members and 211 passengers, in Miami on Aug. 14, 1980.

Forty minutes into the flight they took out a container of liquid they said was gasoline and threatened to start a fire, according to investigators.

They were flown to Havana, where they were arrested by Cuban authorities, Miller said. Federal Aviation Administration records show that Fonseca was later sentenced to five years in a Cuban prison and Garcia was sentenced to four years.

The hijacking came during a rash of such crimes by homesick Cubans in late summer 1980, a few months after nearly 125,000 Cubans sailed to Florida from the port of Mariel, some unwillingly.

The hijackings abated after Fidel Castro warned that anyone who went to Florida in the ''Freedom Flotilla'' would face severe punishment if they hijacked planes to return to Cuba.