A Chinese marine research ship was extending something like a pipe into the sea in the Japanese exclusive economic zone off the Senkaku Islands in Okinawa Prefecture Sunday, the Japan Coast Guard said.

BEIJING — The reason Chinese President Xi Jinping’s administration resumed its intrusions into Japan’s territorial waters around the Senkaku Islands in Okinawa Prefecture from Sunday to Tuesday appears to be a desire to demonstrate its refusal to compromise on its territorial claims amid a wave of developments affecting regional affairs in the Asia-Pacific region, including the inauguration of Japan’s new Cabinet and the U.S. presidential election approaching in November.