McDonald's Corp will add chicken sandwiches to its breakfast menu at all of its U.S. restaurants, the world's largest burger chain said on Tuesday, to fend off competition from Chick-Fil-A and Popeyes Louisiana Kitchen.

Breakfast has been an important sales driver for fast-food chains and as more rivals like Wendy's and Dunkin' move into the space with new products, the pressure to retain customers has become more intense.

Earlier this month, McDonald's expanded its Beyond Meat vegan burger trials in Canada, catering to the growing demand for plant-based proteins in fast-food restaurants.

Many experts said a nationwide rollout of chicken sandwiches and not plant-based options would put McDonald's ahead in the fast-food battle.

"We're giving our customers more of what they crave: mouthwatering chicken and breakfast options," the company's vice president of menu innovation, Linda VanGosen, said in a statement. 

The latest breakfast additions to McDonald's menu are - Chicken McGriddles and McChicken Biscuit sandwiches. They are available at participating restaurants for a limited time while supplies last.

The launch comes after the chain tested a crispy chicken sandwich in Texas and Tennessee late last year.

McDonald's is scheduled to report its fourth-quarter results on Wednesday.

(Reporting by Nivedita Balu in Bengaluru; Editing by Arun Koyyur) ((Nivedita.Balu@thomsonreuters.com; within U.S. +1 646 223 8780; outside U.S. +91 80 6749 4822/ Twitter: @niveditabalu;))