The coast guards of Taiwan and Japan have conducted a joint search and rescue drill, with one of the island's vessels recently making a refueling stop in the country, Taiwan authorities said Thursday.

Following the previous one in Japan last year, the refueling stop was made as part of the Taiwan coast guard's high seas patrol mission to protect fishing boats. The patrol vessel, which departed from Kaohsiung Port on June 21, is expected to return to Taiwan on Aug. 14, the coast guard said.

In June, a different Taiwan coast guard vessel anchored in Honolulu during a similar fishery patrol mission, according to Taiwanese media.

The moves may suggest Taipei has been strengthening cooperation with Tokyo and Washington despite the lack of official diplomatic ties amid Beijing's increased pressure on the self-ruled island. China regards Taiwan as part of its own territory.

Taiwan's coast guard cooperates with the island's Fisheries Agency to carry out two or three high-seas fishery patrol missions every year, the coast guard said.

Related coverage:

Japan, U.S., South Korea begin new military exercise to counter North Korea

U.N. Security Council split over North Korea failed satellite launch

FOCUS: Asia security may be at risk if Japan-South Korea ties sour again