Maryland Republican leaders acknowledged today that they used a squad of uniformed private security guards to help challenge possible voting irregularities in black precincts here Tuesday, but denied that the effort was racially motivated or calculated to intimidate voters.

Use of the 12-member roving squad, described by state election officials as unprecedented in recent Maryland electoral history, triggered complaints from predominantly black precincts in west Baltimore.

Investigators dispatched by the state attorney general's office said they confirmed that at least three of the 12 officers carried sticks and chemical spray dispensers and that others were alleged to have misrepresented themselves as "official state monitors."

"If they did abuse any people," said state GOP Chairman Allan C. Levey, "I apologize for it."

Maryland Reagan-Bush campaign manager Bo Denysyk, who helped plan deployment of the security guards, said the officers were supposed to minimize the "military aspects" of their uniforms, and said inclusion of sticks and chemical spray by some "frankly was an oversight."

Maryland Attorney General Stephen H. Sachs, a Democrat, said use of the guards had "no other effect than to intimidate . . . . It is overkill, grossness . . . to have military types patrolling precincts."

The guards, Denysyk said, were provided free of charge by Howard Security Services Inc., a Baltimore-based firm, to supplement what he said was a too-small group of 60 to 70 volunteers assigned as "poll challengers" in precincts where there has been a pattern of "alleged irregularities in the past five to 10 years." He said selection of the precincts was unrelated to the fact that most were in black residential areas.Denysyk said Howard Security is owned by Melvin Bilal, a "recently converted Republican," who has provided other security services to the GOP. Bilal could not be reached for comment.

Denysyk said the officers, traveling in two-man teams, wore the green trousers, white shirts and green ties of the security company, but were told not to carry weapons and to minimize insignia.

Assistant State Attorney General Jack Schwartz, assigned to monitor poll irregularities, said he received several complaints that the guards violated election laws by talking directly to voters, rather than filing challenges with precinct officials.

Denysyk said both the guards and other GOP poll challengers filed 50 complaints of irregularities, including allegations that some voters cast multiple ballots and others were assisted in voting booths by Democratic precinct officials.