TOKYO » Japan would not rule out stationing government officials on islands at the center of a territorial spat with China, the top Cabinet secretary warned Tuesday (Monday in Hawaii), as a fleet of Chinese patrol ships entered disputed waters amid tensions in the year-old maritime standoff.

The fight over the uninhabited islands in the East China Sea, known as Senkaku in Japanese and Diaoyu in Chinese, has tainted relations between the two countries even as they continue to depend on each other for trade.

On Tuesday, seven Chinese patrol ships entered waters around the islands, the latest of many such incursions into the area, according to the Japanese Coast Guard.

A day earlier, the Japanese spotted an unmanned drone aircraft in the islands’ vicinity, and scrambled fighter jets. Japan has not confirmed what nation controlled the drones, but has approached China over the incident, the government said.

The incidents prompted a warning from Japan’s chief Cabinet secretary, Yoshihide Suga, who told reporters that Tokyo stood prepared to make “a calm but resolute response to defend our territory.”

Asked by a reporter whether Tokyo might station officials on the islands to defend Japanese territory, Suga said the move was “one option” under consideration.

“Our country will never make a concession on the matter of sovereignty,” he added.

An effort by either country to forcibly control the islands could lead to an escalation of the conflict, strategists have warned. They also worry that a small, unintended incident at sea as Japanese and Chinese boats chase each other near the islands could lead to a wider conflagration. Open hostility between China and Japan, an important U.S. ally in the region, also risks drawing the United States into the conflict.

The spat presents Washington with an unwelcome distraction as President Barack Obama presses for a military strike on Syria.

The territorial dispute, which has lasted for decades, flared up last year after the Japanese government bought three of the five islands from their private owner. The move drew outrage from Beijing, which saw it as an effort by Japan to solidify its claims. Tokyo had said at the time it was acting to pre-empt nationalists from trying to take more provocative steps to assert control.