The U.S. Federal Communications Commission approved rules yesterday that allow publishers to own both newspapers and broadcast stations in the biggest American cities and that limit growth for cable companies.

The chairman of the commission, Kevin Martin, and the other two Republicans on the five-member panel backed the loosened rules for newspaper owners, which modify a ban adopted in 1975. Mr. Martin joined the agency’s two Democrats in approving the cable limit.

Publishers Tribune Co. and News Corp. had said the ownership proposal didn’t go far enough, while consumer groups said it threatened diversity in local press and broadcast. The FCC disregarded 25 American senators, who vowed in a letter released Monday to block the decision. They said more time is needed to review a policy that has “a substantial impact on the American people.”

“The media marketplace is considerably different” than when the rule was put in place 32 years ago, Mr. Martin said just before the vote. “Allowing cross-ownership may help to forestall the erosion in local news coverage by enabling companies to share news-gathering costs across media platforms.”

Tribune, based in Chicago, rose $1.02, or 3.2%, to $33.31 at 4:03 p.m. in New York Stock Exchange composite trading. The shares have gained 8.2% this year. News Corp. Class A shares, down 5.7% this year, gained 23 cents to $20.26.