HARRISBURG, Pa. — In his second out-of-state trip within a week, Mayor Bloomberg took his gun-control message to Pennsylvania’s capital, telling state lawmakers that their weak gun laws are hurting New Yorkers.

“The fact is what happens in Pennsylvania or any other state doesn’t stay in Pennsylvania or any other state,” Mr. Bloomberg said yesterday during a news conference. “All of us are affected by its weak guns laws.”

The trip to Pennsylvania came on a day that a congressional committee in Washington passed a bill to alter the way guns laws are enforced at the Bureau of Alcohol, Tobacco and Firearms.

Mr. Bloomberg and the group of seven mayors he appeared with yesterday, including Philadelphia’s mayor, John Street, say that bill makes it more difficult, not easier, to crack down on illegal guns. He said the “disastrous legislation” would “protect criminals.”

Mr. Bloomberg said the coalition of mayors he’s organized, which now includes about 80 mayors, would lobby to defeat the ATF bill if it made it to the Senate. He also called on voters to hold Congress accountable in November’s midterm elections. Sponsors of the bill in Washington defended it as a bipartisan effort that would reform the ATF.

“I think you should call your congressman and say now wait a second, you just asked me to vote for you on November 7 and you’re doing what to my children?” Mr. Bloomberg said.

“The public got to understand who they’re being asked to vote for when they go to the ballot box,” he said.

The trip to this capital city was part of the mayor’s larger effort to cut off the flow of illegal guns into New York City. But with trips to California, Georgia, Maryland, Illinois, and Washington, D.C., dotting his schedule in the last couple of months, questions about whether he is trying to introduce himself to out-of-state voters for a possible 2008 presidential run continue to swirl.

Yesterday, activists on both side of the gun issue flooded into capitol building here as the state’s Republican-controlled General Assembly considered a dozens of anti-violence bills.

The mayors lobbying for restrictions on guns purchases and other measures will have a decidedly uphill battle with Second Amendment advocates gearing up for a fight.

Mr. Street said there are too many registered weapons in his city. He noted that New Jersey has about 4,000 licensed gun owners, and that New York City has about 15,000. Philadelphia, he said, has about 31,000. “That’s way too many people authorized to carry a deadly weapon,” he said.

For Mr. Bloomberg, being in Pennsylvania was another chance to stake out his positions for a wider audience. Last week, he was in California for events with the mayor of Los Angeles, Antonio Villaraigosa, and with Governor Schwarzenegger.

A retired Spanish teacher from Philadelphia, Sandy Dunn, who traveled to Harrisburg yesterday, said she was happy to see Mr. Bloomberg fighting what she called the state’s “criminal” gun laws.

Others had a different take. A Second Amendment advocate, Harry Sills, said Mr. Bloomberg is trying to take away all civil rights.

“If it was up to him you wouldn’t be able to smoke, drink, own a gun, or do much of anything,” Mr. Sills, who traveled to the capital from Pittsburgh, said.

A Philadelphia minister who joined the mayors, the Reverend William Shaw, equated the gun control fight to the recent E. coli outbreak. “If you can trace spinach to a farm, why can’t we trace guns to a gun dealer?” he said.