Officials in the Philippines have apologized to China for using a logo of the Taiwan defense ministry during a ceremony to mark the handover of assault rifles and ammunition from Beijing to the Filipino military.

Defense secretary Delfin Lorenzana described the error as a technical lapse that was “grevious but purely unintentional”.

The Taiwanese logo was displayed on a huge banner that hung above the Chinese ambassador, who attended the ceremony at a barracks in Quezon City last week and sat near Lorenzana and Philippine army chiefs.

China handed over 3,000 rifles and 3 million rounds of ammunition last Thursday.

The Philippine Department of National Defense noted that their government adheres to the ‘One China Policy’ and hoped that the incident would not affect warmer ties between the two countries.

The Philippines has moved closer to China, away from its traditional ally the United States since last year, when Rodrigo Duterte became president. Duterte has played down heated territorial disputes in the South China Sea, which had undermined ties during the reign of his predecessor Benigno Aquino, in the hope of attracting Chinese investment.

Fighting has raged in Marawi in Mindanao in the south of the Philippine archipelago since May, when fighters inspired by Islamic State attempted to take over the city. Nearly 1,000 people have been killed.

Beijing made a previous donation of weapons and ammunition to Manila at the end of June.