The American Ballet Theatre has again parted company with its two most controversial and outspoken performers, superstar Gelsey Kirkland and leading dancer Patrick Bissell.

Kirkland, regarded by many dance experts as the greatest American-born ballerina of our time, has been unable to reach agreement on a new contract with ABT artistic director Mikhail Baryshnikov, sources said. Bissell was informed last weekend that he is not currently welcome at ABT, the sources added.

More details of the Kirkland-Bissell-ABT breach could not be obtained immediately.

Both dancers had been fired last December by ABT for alleged unreliability on the eve of the company's Washington season. The two of them were rehired during the final days of ABT's spring Washington season this year.

Bissell, Kirkland and ABT officials with current knowledge of the situation were not available for comment last night.

Bissell, in a recent interview, said he intended to stay with ABT for the rest of his career.

In response to a query, an official of Dube Zakin Management, which represents Bissell and Kirkland, said that ABT had given Bissell "a leave of absence" and that "we are hopeful he will rejoin ABT."

However, a source close to Bissell said the leave "does not sound like a friendly gesture" by ABT.

Last spring, Kirkland had not intended to return to ABT this fall, and had accepted an offer to join Britain's Royal Ballet as a guest artist in September. She postponed her trip to London, however, when a senior ABT official convinced her to rejoin the American company. Since then, she and ABT have not been able to come to contract terms.

Both Kirkland and Bissell missed a number of key rehearsals last season, and had developed a reputation for unreliability.

But after their return to ABT in the spring, they both appeared at all performances for which they were scheduled, with one exception -- when Bissell canceled a performance in June due to an injury.

Kirkland, according to Dube Zakin, will join the Royal Ballet as a guest in December. The Dube Zakin official said both Kirkland and Bissell will fulfill all of their scheduled guest engagements.

Bissell is scheduled to leave this morning for two weeks of rehearsals and performances with a ballet company in Manila, the Philippines.