Media in mainland China have doctored photos of the Chinese activists who landed on the Japan-controlled Senkaku Islands, deleting or masking a Taiwanese flag held up by one while leaving Chinese flags on display, local media reported.

The seven activists who landed on the islet of Uotsuri in the East China Sea were seen holding one Taiwanese and two Chinese flags in a photograph taken by a journalist aboard the Hong Kong vessel they sailed on.

Mainland China TV and newspapers that carried the photo Thursday either covered over the Taiwanese flag with headlines or edited it out altogether, the Hong Kong-based Ming Pao Daily said Friday.

The Xiamen Economic Daily, headquartered in the southeastern province of Fujian, issued an apology after drawing flak from readers for doctoring the Taiwanese flag to make it appear red.

"Our newspaper inappropriately used (Photoshop editing) and hurt the feelings of our readers," it said Thursday in a statement on its blog. "As a responsible media organization, we should not have made such mistakes. We apologize to all readers."

Academics quoted by the newspaper said hostility toward Taiwan's Nationalist Party is still deeply embedded among press watchdogs in the Chinese Communist Party.

Japan annexed the Senkaku islets in 1895 but they were briefly placed under Allied control during the postwar occupation, before being returned to Tokyo in 1971. China and Taiwan both claim the uninhabited isles because of their vast fisheries resources, as well as presumed gas and oil deposits under the surrounding waters.