The US military apologized after soldiers accidentally stormed an olive-oil factory in Bulgaria

• US Army soldiers accidentally stormed a private business during training in Bulgaria.
• The service issued a statement saying that it "sincerely" apologizes for the mistake.
• The incident triggered sharp criticism from the Bulgarian president.

The US Army issued an apology this week after soldiers accidentally stormed a factory in Bulgaria during a training exercise last month.

During Exercise Swift Response 21, soldiers with the 173rd Airborne Brigade practiced seizing and securing the Cheshnegirovo airfield. Soldiers stormed and cleared bunkers and buildings across the decommissioned airfield.

"On May 11, soldiers entered and cleared a building next to the airfield that they believed was part of the training area, but that was occupied by Bulgarian civilians operating a private business," US Army Europe and Africa said in a statement on Tuesday.

The private business, CNN reported, was a factory that makes processing machinery for the production of olive oil.

The Army said in its statement that no weapons were fired during the incident, which was caught on the factory's security cameras. As Task & Purpose said in its report, a Bulgarian reporter posted the following video on Twitter.

"The US Army takes training seriously and prioritizes the safety of our soldiers, our allies, and civilians," the service said. "We sincerely apologize to the business and its employees."

The Army is investigating the incident so that it can determine the source of the mistake to make sure that training areas are clearly defined for future exercises. An Army spokesperson told Task & Purpose that no soldiers had been disciplined.

Though there don't appear to have been any injuries from the unintentional incident, Bulgarian President Rumen Radev expressed great displeasure with these developments, reported Nova TV, a local CNN affiliate.

In discussions with his defense minister and the commander of Joint Forces Command, Radev said that "it is inadmissible to have the lives of Bulgarian citizens disturbed and put at risk by military formations, whether Bulgarian or belonging to a foreign army."

"The exercises with our allies on the territory of Bulgaria should contribute to building security and trust in collective defence, not breed tension."

Exercise Swift Response 21 was a multinational exercise involving more than 7,000 paratroopers from 10 countries, the US military said. The goal of the exercise was to practice rapidly inserting ground forces for crisis response.

The drill, which lasted from May 10 to May 14, was a part of the larger Defender Europe 21 exercise, which involves over 28,000 troops from 26 countries.