Nine Nigerian citizens have been arrested on drug trafficking charges during raids in which about three pounds of high quality heroin with an estimated street value of more than $3 million were seized, federal authorities said yesterday.

Robert O'Leary, a spokesman for the Drug Enforcement Administration, said the New Year's Eve raids followed a seven-month undercover investigation that concluded with the arrest of Lawrence Kuteyi, 29, of 2400 Brightseat Rd., Landover, after he allegedly tried to sell 28 ounces of the drug to agents on a downtown street. Tony O. Abiola, 33, who O'Leary said acted as a lookout during the transaction, also was arrested.

Federal agents later raided an apartment at 7000 Hanover Pkwy., Greenbelt, where seven other Nigerian citizens -- six men and a woman -- also were arrested, and 18 ounces of the drug that had been tossed from a window and $26,000 in cash were confiscated.

O'Leary said tests of the drugs revealed they were of unusually high purity.

He speculated that those arrested were allegedly part of a large-scale operation in the metropolitan area.

"This was not a nickel-and-dime organization," O'Leary said. "The drugs which we seized were certainly above 50 percent pure, which for this area is phenomenal because the average purity of what you find on the street is only about 5 percent."

Also arrested and charged with conspiracy to distribute and possession with intent to distribute heroin were Alexander Fadugua, 26; Dotun K. Akinwale, 22; Victor Vivour, 27; Daniel Lawal, 39, and Yejisolan Benson, 25, all of the Hanover Parkway address.

Two other men, Clement Babeyemi, 52, with no local address and Anthony Onianwah, 24, of 5802 Merton Ct., Alexandria, were also charged in the alleged operation.

All were being held last night without bond, O'Leary said.