WASHINGTON (AP) _ Mayor Marion Barry was indicted on six additional drug charges today alleging he possessed cocaine on several occasions from the fall of 1984 until his arrest last January in an FBI sting operation.

Barry was charged with one misdemeanor count of conspiracy to possess cocaine and five misdemeanor counts of possession.

The conspiracy count alleges that from the fall of 1984 until Barry's arrest in January, the mayor ''obtained, possessed and used cocaine powder and crack with more than 10 persons at more than 20 locations, including private residences, hotels, business establishments and government offices, both inside and outside the United States,'' said a statement released by U.S. Attorney Jay B. Stephens.

Barry, 54, was first indicted Feb. 15 on five misdemeanor counts of cocaine possession and three felony counts of lying to a grand jury about his alleged drug use. He pleaded innocent.

Following his arrest, Barry spent several weeks in rehabilitation facilities in Florida and South Carolina for treatment of what he said was alcohol and prescription drug abuse.

Barry's mayoral term ends this year but he has not yet said whether he would seek re-election.

In recent weeks, Barry has been touring the city and speaking to a wide array of community groups in a series of campaign-style appearances.

However, if Barry is convicted of a felony, he would be barred from holding office or running for re-election.

The same grand jury returned today's indictments. Barry is scheduled to go on trial June 4 on all 14 charges.

Barry has consistently denied any drug use despite an FBI videotape that sources have said showed him smoking crack cocaine in a hotel room with a woman who was cooperating with the investigation.

The indictment did not name any of the other individuals Barry allegedly used cocaine with.

Conviction on the conspiracy count and each of the possession counts would carry penalties of up to one year in prison and a fine of $100,000.

The February indictments alleged five misdemeanor counts of cocaine possession and three felony counts of lying to the same grand jury about his alleged drug use.

One of those charges stems from Barry's Jan. 18 arrest in the FBI sting operation at a downtown hotel; the other seven charges result from a 14-month probe into the mayor's ties to a convicted drug dealer.

Opinion polls indicate Barry would have support from about 20 percent of the community if he were to enter a race that already includes five candidates for the Democratic mayoral nomination. City law does not require that a candidate win a majority of the vote, meaning he could be re-elected on the basis of his current levels of support in this heavily-Democratic city.

05-10-90 1419EST