MANILA, Philippines — The Philippine defense department has apologized to China for the “grievous but purely unintentional mistake” of using Taiwan’s defense ministry logo during a ceremony where the Chinese ambassador turned over thousands of assault rifles to the Filipino defense chief and top military commanders.

The Department of National Defense said Monday that Secretary Delfin Lorenzana issued an official apology to China through Beijing’s ambassador over the “technical lapse” in last week’s ceremony, which was covered by the media at military headquarters.

The defense department did not say in its press statement which country owned the defense logo it displayed instead of the emblem of the China’s defense ministry.

A Philippine official told The Associated Press it was Taiwan’s, adding that Chinese officials called the attention of the Philippines about the faux pas. The wrong logo was printed on a huge banner that was hung prominently above Chinese Ambassador Zhao Jianhua, who was sitting on a red carpet and planked by Lorenzana and the Philippine military chief of staff.

It took a few days before officials discovered the error.

During the symbolic handover ceremony of 3,000 rifles and 3 million rounds of ammunition Thursday, “the Department of National Defense committed a grievous but purely unintentional mistake of using a different logo on a banner to represent the Ministry of Defense of the People’s Republic of China,” the Philippine defense department said.

The defense department stressed that it and the military adhere to the “One China policy,” wherein the Philippine government recognizes only the People’s Republic of China as the sole sovereign state.

“It is our sincere hope that this very unfortunate incident will not affect the cooperative and friendly relations between our two countries which has grown warmer over the past year,” the department said.

After he took office last year, President Rodrigo Duterte immediately took steps to revive once-frosty relations with China while taking an antagonistic stance toward security policies of Manila’s treaty ally, the United States.

Duterte has sidelined long-raging territorial disputes with China in the South China Sea in an effort to attract Chinese investment and infrastructure funds. He has promised, however, to take up with China at an unspecified time in the future an international arbitration ruling that invalidated Beijing’s claims to most of the disputed waters.