"Breakfast all day is certainly something we'll always take under consideration, but I can fairly tell you it's not something that is going to happen for a long time," McDonald's USA Chief Operating Officer Jan Fields said in a webcast news conference.

Breakfast accounts for 24 percent of McDonald's Corp.'s U.S. sales and 28 percent of transactions, she said.

While it is McDonald's USA's most profitable meal, Fields would not say what percentage of company earnings come from it.

The world's largest fast-food chain, which has increasingly focused attention on breakfast -- recently introducing a stronger "premium roast" coffee -- began selling a McSkillet Burrito nationwide Tuesday.

The $2.49 tortilla is folded over a filling of scrambled eggs, a sausage patty, potatoes, roasted peppers, onions, cheese and red salsa, the company said.

It contains 610 calories, 1,390 grams of sodium and 36 grams of fat, including 14 grams of saturated fat and 0.5 grams of trans fat, The Chicago Sun-Times reported.

Rival Wendy's International Inc. is also rolling out a breakfast menu. Burger King Corp. introduced a low-priced breakfast menu last year. Starbucks Corp. (NASDAQ:SBUX) offers breakfast sandwiches.

Jack in the Box Inc. restaurants serve the entire menu, including breakfast, all day.