Democrats and Republicans in Alexandria selected their slates yesterday for spring's City Council elections.

In a pair of caucuses that attracted hundreds of loyalists who cast ballots over several hours, both parties nominated their incumbent council members, then rounded out their six-member tickets with a range of challengers. The general election will be May 6.

Winning Democrats included incumbents Joyce Woodson and Redella S. "Del" Pepper, who will be joined by Planning Commissioner Ludwig P. Gaines, geology professor Andrew Macdonald, civic activist Kenneth R. "Rob" Krupicka and former city party chairman Paul Smedberg.

Republicans nominated incumbent Claire Marie Eberwein and challengers Judy McVay, a longtime neighborhood activist, businessman John Reardon, financial consultant Keith D. Burner, Parkfairfax civic association President Matthew Natale and businesswoman Allison Cryor.

Mayoral candidates William Euille (D), a council member, and William C. Cleveland (R), a council member and vice mayor, have secured their party nominations without opposition. In the May election, they face each other and Townsend Van Fleet (I), a longtime city activist and Washington lobbyist.

Democratic and Republican officials said their nominees include some of the most experienced candidates they have seen in several election cycles and predicted a competitive campaign. The three council incumbents running for reelection said it probably will be a tough 12-week campaign.

Republicans said they are more enthusiastic than they have been in years about their chances this spring in largely Democratic Alexandria. There are four Democrats and two Republicans on the council, and GOP leaders hope to increase their strength.

"We think the city is ready for a change," said C. Kelly Skrabak, chairman of the Alexandria Republican City Committee, after the party's candidate forum last week. The city has not had a Republican mayor since Reconstruction and has never had a Republican majority on the City Council, party officials said.

It has been a tense campaign season for both parties. Twelve Democrats, including the two incumbents, competed for the six spots on the ticket -- the most in recent memory. In two candidate forums last month, hopefuls addressed issues that plague many of the region's inner suburbs, including how to balance complaints of increasing density and traffic with the need for development that can boost commercial real estate tax revenue. Republicans held their first caucus in a dozen years because there is so much interest.

Sensing a tight race, candidates in both parties intensified their campaigning late last week and yesterday, with Woodson and Gaines transporting voters to the Democratic caucus in vans. Supporters of other aspiring nominees spent the last hours making phone calls encouraging Alexandrians to vote and planted signs near polling stations in the early morning.

The intense interest in the campaign has been generated largely by the number of council openings. Not only is Mayor Kerry J. Donley (D) stepping down, but Cleveland and Euille are relinquishing their seats to run for mayor. After serving three terms, council member David G. Speck (D) is retiring.

In addition to development and density issues, party officials said, the three-month campaign season probably will focus on school needs and taxes.

The city plans to spend $75 million to replace its only high school, and some Republican candidates are questioning that price tag and council members' spending priorities. Real estate assessments, as in all of Northern Virginia, are expected to increase by nearly 15 percent, and Republicans have vowed to help ease the tax burden on residents.

"This city has spent way too much over the past several years," said Reardon, the Republican nominee and chief executive of a wireless communications company. "One of the clear messages that our party needs to send is that we can do better by our citizens and not only help cut their taxes but also streamline city spending."