Laura Whitehorn and Linda Evans, self-described freedom fighters convicted of conspiracy in the 1983 bombing of the U.S. Capitol, were sentenced yesterday by U.S. District Judge Harold Greene to 20 and five years, respectively.

In a courtroom crowded with sometimes raucous supporters, the two women told Greene in separate appearances that they are not criminals or terrorists, but fighters for the cause of freedom of black people and oppressed people everywhere.

"It was not a thirst for violence which motivated me," said Whitehorn, who entered the courtroom with a clenched, raised fist, a silent greeting returned by her supporters. "It was a thirst for liberation, a thirst for justice, a thirst for peace."

But Greene told Whitehorn that she had "committed acts of violence which are not excused by good purposes. They are just as devastating to the victims as if they had been motivated by greed."

He ordered Whitehorn, 43, to serve 20 years in addition to the 5 1/2 years she already has spent in prison, partly in preventive detention and partly on an unrelated passport fraud charge. The sentence, the maximum Greene could have imposed, drew hisses from the crowd.

Evans, also 43, will serve her five-year sentence in addition to a 35-year sentence she is already serving on a related firearms conviction in Louisiana. Greene, citing the lengthy sentence imposed in the Louisiana case, said he would not impose the 10-year maximum.

Yesterday's hearing marked the end of a lengthy government prosecution of a group of alleged terrorists who participated in a series of bombings in the early 1980s.

Besides the Capitol bombing, which damaged a conference room near the Senate Chamber, prosecutors said the conspiracy included the bombing of the National War College at Fort McNair in April 1983, the bombing of the Washington Navy Yard computer center in August 1983, and the bombing of the officers' club there in April 1984.

As part of a plea agreement made public in September, Whitehorn and Evans pleaded guilty to charges of conspiracy and malicious destruction of government property. In exchange, prosecutors dropped other charges against them and three of their co-defendants, Timothy Blunk, Susan Rosenberg and Alan Berkman. Berkman, who is serving a 10-year sentence on a firearms conviction in Pennsylvania, did not appear at yesterday's hearing. He is confined to D.C. General Hospital, where he is undergoing chemotherapy for Hodgkin's disease.

Rosenberg and Blunk, who are both serving 58-year sentences on explosives and firearms convictions in New Jersey, appeared in court just long enough to hear Assistant U.S. Attorney Peggy Ellen drop the charges against them.