People eat at a McDonald's restaurant in Seoul, May 1. Yonhap

McDonald's Korea has been forced to take tomatoes out of its burgers, due to a supply shortage caused by the record-breaking heat wave this summer, the local unit of the fast food giant said Tuesday.

The company decided to offer free drink coupons to customers who ordered burgers that were supposed to come with tomatoes.

"We thank you for your patience and kind understanding," McDonald's Korea said in a statement.

"McDonald's is committed to stabilizing the tomato supply as soon as possible."

McDonald's Korea has sourced around 2,000 tons of tomatoes annually from Korean farmers to support local communities and secure high-quality ingredients.

According to the Ministry of Agriculture, Food and Rural Affairs, the sweltering heat especially damaged tomatoes harvested in Jangsu County, North Jeolla Province, and Cheorwon County, Gangwon Province.

In June, McDonald's Korea was also forced to halt sales of French fries because of concerns about "substandard" frozen potatoes from the United States.

It resumed sales of French fries about a week after the suspension.

In 2020, the Korean units of McDonald's and Burger King served burgers without tomato slices, due to the longest rainy season in the country's history.