(ECNS) -- A bakery promotion tied to China's "520" romantic holiday sparked criticism online after referencing a recent earthquake in an advertisement for themed cakes.

In a social media post promoting its May 20 products, the bakery wrote that a "5.2-magnitude earthquake arrived before 520," referring to a recent tremor in Liuzhou, before encouraging customers to celebrate the holiday with cake.

The post continued by urging people not to miss "the chance to eat cake with important people," adding wishes for "peace, love, and sweetness forever."

"520," pronounced wu er ling in Chinese, is widely used online as shorthand for "I love you" because of its similar pronunciation in Mandarin. The date, May 20, has become an informal Valentine's Day in Chinese popular culture and is heavily used in marketing campaigns.

Some social media users accused the bakery of exploiting a natural disaster to attract attention and drive sales, calling the advertisement insensitive and inappropriate. Others defended the post as dark humor designed to stand out in China's crowded online advertising environment.

Following the backlash, the shop issued an apology, saying it had deleted the original post immediately and sincerely accepted all criticism.

In a statement released by the market supervision administration of Qixing District on Tuesday, authorities said they have launched an investigation into the promotion case.

The bureau also reminded all market entities to conduct commercial marketing legally and to refrain from publishing inappropriate information that capitalizes on natural disasters, major accidents, or other tragic events.

(By Zhang Dongfang)