Mayor Martin O'Malley submitted a plan yesterday that significantly reshapes the City Council for the first time in decades, a map that threatens to pit incumbents against one another, is likely to disrupt neighborhood alliances and creates the rare chance for a Republican to be elected to the council.

At a news conference yesterday, O'Malley reiterated his opposition to shrinking the council from six three-member districts to a setup mandated by voters in November that establishes 14 single-member districts. O'Malley said that in redesigning the city's council districts, he tried to minimize the impact on incumbents.

"I think it's a pretty good map," he said. "We have respected the diversity of the city."

Several council members had been worried that new, single-member districts would threaten the African-American majority on the council. O'Malley's map proposes 12 districts that are predominantly African-American and two that are predominantly white. Each district represents populations between 44,434 and 48,925.

The map has already touched off a political maelstrom that is expected to last for the next 60 days as the council debates the mayor's plan in private and during public hearings in February.

"This will be the single most important vote they make as council members," said Arthur Murphy, a political consultant. "And it will be made mostly in back rooms."

Although the council has scheduled two public hearings, Feb. 19 and 20, council members were scattered throughout City Hall all day discussing the implications of the map.

"It's hard to say who's in and who's out," O'Malley said. "There is no prohibition against a council member moving."

That's just what Councilman Melvin L. Stukes might do. Stukes and Councilman Edward L. Reisinger are expected to compete in the new 10th District, a predominantly white district that encompasses South Baltimore, Federal Hill and parts of the Inner Harbor.

"I always saw this as a tool to diminish the electoral base of the African-American community," Stukes said.

Two other districts were drawn that would pit other council members against one another. Council members Nicholas C. D'Adamo Jr. and Lois A. Garey would compete in the new 2nd District, which includes 50.5 percent black voters in the east and northeast corner of the city; council members Pamela V. Carter and Bernard C. "Jack" Young are expected to compete in either the new 12th or 13th, both predominantly black districts in the center and eastern parts of the city.

O'Malley's plan has left John L. Cain as the sole council member residing in the new 1st District in southeast Baltimore, including Canton. That might allow him to escape having to run against D'Adamo and Garey, his current colleagues in the existing 1st District, but it opens him to a challenge from Republicans.

"That's where I would run if I do run," said Robert Santoni Sr., chairman of the Republican Party Central Committee of Baltimore City. "I really want to run but it will require relocating."

Santoni said he would have to move from Harbor Court near the Inner Harbor to Canton in order to run against Cain in a district that showed support for Republicans in the past.

"Everybody is nervous," Cain said. "I don't know what's going to happen."

Councilwoman Rochelle "Rikki" Spector said she is "very concerned about a court challenge" to the plan.

But O'Malley said he is not worried about the possibility of a challenge similar to one that led to the dismantling of Gov. Parris N. Glendening's statewide redistricting plan. The mayor said he expects legal challenges from lawyers who, he said, were making a "cottage industry" out of challenging redistricting plans in Maryland. But he was confident his staff had crafted a bill that adheres to state and federal laws.

One citizen group that helped place the redistricting question on the ballot in November was quick to express its displeasure after a brief glimpse of the plan.

"It seems as if they're giving preference for incumbency over the continuity and compactness of neighborhoods and of community interests," said Sultan Shakir, organizer of ACORN. "[The plan] has split Park Heights in two districts, one shaped like an eagle."

O'Malley said it was inevitable that some neighborhoods would be split. He also said several community organizations even requested that their neighborhoods be split in order to have two council members to call on instead of just one.

"Ashburton wanted to be split," O'Malley said.

He said many community groups had sent him their recommendations and all of them were considered in the final draft of the map.

Shakir disagreed.

"There was no real community input, no serious effort to have community input," he said. His organization was planning a meeting this morning to hash through the details of a map that many found confusing yesterday despite three meetings at which the council discussed the mayor's redistricting plan.

O'Malley introduced his plan to the council during a private luncheon at his offices. The council then invited John T. Willis, former secretary of state and the chairman of Glendening's redistricting committee, to discuss how the council could change the mayor's plan without violating state and federal law.

Several neighborhood organization leaders attended the meeting, hoping to hear details related to the map. Instead Willis, who also had not seen the new map until minutes before the meeting and was uncertain of what the council expected of him, fielded general redistricting questions from the council.

Councilwoman Paula Johnson Branch asked that the map not be discussed. "I would advise council not to introduce or distribute the map," Branch said at the start of the meeting. She felt the plan could change even by the end of the day.

Political observers and the politicians themselves were further confused because on the map available to them, the new 14 districts were not designated by community names or street boundaries - just blocks of different colors representing city neighborhoods.

O'Malley has said from the beginning that everyone would be disappointed with his map.

"This was a heartbreaking and painful process," he said.