SCRANTON -- Hazleton Mayor Louis Barletta testified yesterday that his city needs another 30 police officers, but his crime-fighting priority has been creating laws to kick illegal immigrants out of town.

During five hours on the witness stand, Mr. Barletta said Hazleton is being ruined by violent crime, crowded schools and a clogged emergency room at the city's private hospital. He attributed many of the problems to what he called "illegal aliens," even though he admitted he had no idea how many such immigrants are in his city.

Lawyer Witold Walczak, of the American Civil Liberties Union, got the mayor to concede that he could not name a single instance where illegal immigrants had received service from Hazleton's fire department or health officer. Mr. Barletta also was forced to admit he had no proof that illegal immigrants were the source of schools so crowded that numerous classes have to be taught in trailers.

The ACLU is among the civil rights groups that sued Hazleton over its immigration ordinances. Mr. Walczak and other opponents of the laws say the mayor is willing to run roughshod over innocent people, mostly Spanish-speaking newcomers, in his zeal to find illegal immigrants.

Two of the laws would punish businesses that hire illegal immigrants and landlords that rent to them.

Another ordinance would force every prospective renter to appear at city hall with proof of his U.S. citizenship or legal right to be in America. Hazleton would be the only city in the nation with such an investigative system for tenants.

U.S. District Judge James Munley has stopped the laws from being enforced until the issue of their constitutionality is decided at trial.

Mr. Barletta said the ordinances are necessary to stop crime. Mr. Walczak jumped on the comment, telling the mayor it was unrealistic to believe crime could be eliminated.

"Especially when you're trying to do it and you're sued," Mr. Barletta said.

Mr. Barletta, 51, frequently was combative and so long-winded that Judge Munley admonished him for making speeches.

The mayor said his estimates show that Hazleton's population has jumped from 22,000 to 33,000 in six years, mostly because of Latino newcomers. But the city's police force has shrunk from 42 officers in 2000 to 33 today. Mr. Barletta said Hazleton should have more than 60 police officers.

He said Hazleton, with a government budget of about $7.5 million, simply cannot afford to hire more police. But under pressure from Mr. Walczak, he admitted that the city had not joined a program in which the federal government deputizes local officers so they can assist with immigration enforcement.

The mayor insisted he knew little about how the U.S. government could help his town with illegal immigrants. He said Hazleton's police chief was responsible for finding out about the program.

Still, Mr. Barletta said crimes committed by illegal immigrants led to the controversial ordinances. The most notorious case was the murder last May of a man named Derek Kichline. Two illegal immigrants from the Dominican Republic are accused of killing him.

Shaken by the violence, Mr. Barletta went on the Internet searching for a law to somehow regulate immigration at the local level. He found an ordinance that failed to win approval in San Bernadino, Calif., copied the bulk of it and pushed it through the Hazleton City Council.

The mayor said these measures, if ever enforced, will help solve problems caused by illegal immigrants.

Mr. Walczak, though, said Hazleton's own statistics show that illegal immigrants have committed only a handful of serious crimes. Of the 8,575 felonies in the city since 2000, about 20 were linked to illegal immigrants, Mr. Walczak said.

He tried to question the mayor about these statistics, but the city's lawyers objected. They said questions about crime statistics should be posed to the police chief, not Mr. Barletta.

Judge Munley disagreed, ruling that the mayor must answer questions about the numbers. But he gave Mr. Barletta until today to study so he can be prepared for Mr. Walczak's questions.

Mr. Barletta could be on the witness stand most of today. The trial could last another week.