More than 200 people accused of being Jamaican gang members were in custody Friday as police and federal agents continued sweeps across the country aimed at breaking up violent drug rings that authorities blame for 1,400 murders.

About 435 members of the gangs, or "posses," are being sought in 20 states, out of an estimated total gang population of 10,000, said U.S. Attorney General Dick Thornburgh."The government has alleged that the Jamaican posses are among the largest traffickers in crack cocaine, which is aimed especially at young people," the attorney general said in Washington.

Posse members, known by nicknames like Kong, Storyteller, Stand Steady and Banana, also are accused of drive-by intimidation shootings and cold-blooded multiple slayings around the country.

"They are known to be involved with over 1,400 drug-related murders since January 1985, as well as kidnapping, robberies, assaults, domestic and international gun trafficking, money laundering and fraud," Thornburgh said.

One of those still being sought was Vivian Blake, an alleged ringleader of the Shower Posse who has been identified by various law enforcement officials as the son of a key adviser to former Jamaican Prime Minister Norman Manley.

The Shower Posse is one of more than 40 Jamaican gangs believed operating in the country.

A 62-count indictment unsealed Thursday in Miami charged that Blake and 33 other alleged members of the Shower Posse participated in cocaine and marijuana smuggling, illegal arms purchases and racketeering, including nine killings. "This is the first time that a Jamaican drug gang has been indicted in the United States as an enterprise," said U.S. Attorney Dexter Lehtinen.

Blake, charged with the most serious counts, faces a maximum of 390 years in prison and $15.5 million in fines.

The indictment accused some of the posse members of participating in the execution-style slaying of five people at a Miami apartment in November 1984. One victim was a pregnant woman found in a praying position as if pleading for her life, investigators said. She had been shot six times.

The gangs are known for their elusiveness, changing names and addresses so often that by the time police learn them, they have moved and adopted new names, said Joe Vince, an agent for the Bureau of Alcohol, Tobacco and Firearms.

The posses grew out of gangs formed in the slums of Jamaica and have carriedtheir activities and bloody feuds to the streets of the United States in an effort to expand their control of drug trafficking, officials said.

"They get a lot of young men from the ghettos in Kingston to work for them," Vince said. "They're called `silkies' because the gang buys them a silk suit. They always carry 9mm pistols."

The arrests, which began Wednesday night, cover 20 states but were focused in Houston, Miami and New York, said Stephen Higgins, the bureau's director.

The indictment also accused posse members of involvement in another murder in Miami, one in New York City and two in Los Angeles.

The murders are elements of racketeering charges; there is no federal murder charge that would apply, although murder charges could be brought separately by local authorities.

The indictment also charged the suspects with the illegal purchase of weapons in Dayton, Ohio, and of trying to bribe witnesses in New York to protect the posse from investigation.

The Shower Posse's principal business was smuggling cocaine and marijuana from the Bahamas and distributing the drugs in suitcases to New York, Los Angeles, Detroit, Canada and other locations, authorities allege.

Two of the Shower Posse's four alleged ringleaders, Errol Hussing and Tony Bruce, are in custody in New York, Lehtinen said. Another, Lester Coke, is in jail in Jamaica.

Coke, a well-known Jamaican contractor who has had a high-profile role in Jamaican Prime Minister Edward Seaga's political campaigns, is in jail in Kingston awaiting trial on a murder charge.

Federal agents, with state and local police, were making the latest arrests, which were being coordinated by the Organized Crime Drug Enforcement Task Force representing half a dozen federal agencies involved in combating drug trafficking.

The sweep includes Atlanta; Baltimore; Boston; Chicago; Cleveland; Dallas; Denver; Detroit; Hartford, Conn.; Houston; Kansas City, Mo.;Las Vegas, Nev.; Los Angeles; Miami; New Orleans; New York; Norfolk, Va.; Philadelphia; Raleigh, N.C.; Washington; and Martinsburg, W.Va.