TAIPEI -- Taiwan has seized a mainland ship and seven crew members for allegedly "crossing the line" in waters near Penghu County in southwest Taiwan.

Taiwan's maritime patrol authority told Xinhua Tuesday that the seven crew members were being held for further investigation in Penghu. Their condition was described as normal.

The ship, used for refueling fishing boats, came from Dongdian Port on the mainland, and was caught "crossing the line" on Monday morning, according to Taiwan's maritime patrol authority.

The investigation is still underway, and the crew members may be punished with fines.