China has sent a survey vessel involved in a standoff with Vietnam last year back into that nation’s exclusive economic zone this month, vessel-tracking data shows, in a move likely to fuel tensions between the two countries over their rival claims in the South China Sea.

In January, Indian Navy Chief Admiral Karambir Singh confirmed the constant presence of seven to eight People’s Liberation Army Navy warships in the Indian Ocean Region at any given time. Speaking at the Raisina Dialogue, the admiral warned: “If anyone operates in our region, they have to notify us first”.

China’s independently-developed AG600 large amphibious aircraft has conducted test flights over the sea, according to its developer Tuesday.