Verizon Communications Inc. has told Comcast Corp. that its Verizon-bashing "Don't Fall for FiOS" advertisements are false and asked the cable giant to fix them in a "cease and desist" letter.

Among other advertising claims, Comcast says that a comparable triple-play bundle of TV, phone and Internet service from Verizon can cost $400 more a year, after promotions expire, than one from Comcast.

Verizon would challenge the advertisements' truthfulness through the National Advertising Division of the Councils of Better Business Bureaus if Comcast failed to change them, Verizon vice president Eric Rabe said yesterday.

"The first step is to ask Comcast to take this stuff down," he said, noting that the two companies were making progress in talks over the disputed advertisements. Verizon sent the letter last Thursday.

Comcast retorted yesterday afternoon. "Verizon's been running a negative campaign against Comcast for years and its response to our campaign shows that they can dish it out but they can't take it. As might be expected, the better the advertising and the more traction that it gains with consumers, the louder the competitor will object," said Comcast spokeswoman Jennifer Khoury. She declined to comment on talks of a resolution.

With a weakening market for TV and broadband Internet subscriptions in this deep recession, the nation's largest cable company seems poised to more aggressively battle for every customer.

Company executives warned that the business has weakened to levels similar to late 2008. Business ticked up in early 2009 but softened in April.

Meanwhile, Comcast faces heightened competition from Verizon and AT&T Inc., which are investing billions of dollars into new equipment to deliver TV and Internet in Comcast's core markets. Verizon or AT&T compete in about 25 percent of Comcast's franchise areas.

FiOS has 2.2 million TV subscribers and 2.8 million Internet subscribers. Comcast has more than 24 million cable-TV subscribers and 15 million Internet customers.

Comcast jabbed at Verizon in late 2008, when it mocked FiOS TV for padding its entertainment content with "how-to" videos.

"Don't Fall for FiOS" advertisements appear on Comcast's cable systems around the nation. The Comcast campaign is available at www.comcast.com/getallthefacts.

One entertaining Comcast advertisement pokes fun at the telephone giant with a backhoe tearing up a person's front yard and breaking a water or sewer line, resulting in a geyser. Workmen fail to properly attach a FiOS router box to a home and it falls off.

"Back up, FiOS bill coming through," a FiOS salesman says as the backhoe passes with a stack of paper in its frontloader.

Contact staff writer Bob Fernandez at 215-854-5897 or bob.fernandez@phillynews.com.