The red, white and blue of U.S. flags flew across the United States yesterday, as towns and cities rushed to line streets with the Stars and Stripes in a patriotic response to the worst terrorist attacks on U.S. soil.

Radio stations repeatedly played the national anthem and the country's largest retailer, Wal-Mart Stores Inc., sold 200,000 flags Wednesday and 115,000 Tuesday, compared with 6,000 the same days last year.

Company spokeswoman Sharon Weber would not confirm that some of the store's locations had sold out of flags, but said the company is "working as quickly as possible to replenish those supplies."

In San Francisco, some retail stores removed merchandise from their store windows and displayed U.S. flags instead.

Yesterday, the U.S. House of Representatives called on all Americans to display the flag as a "symbol of solidarity."

In making a similar call to New Yorkers Wednesday, New York Senator Charles Schumer said "displaying the American flag shows that . . . we are not and will not be defeated."

The surge in patriotism is to be expected, according to Mitch Hammer, director of American University's Center for Crisis Response and Management.