Vietnam protested on Friday against what it calls China’s unilateral fishing ban in the disputed South China Sea from May 1 to Aug. 16, weeks after it said Vietnamese boat had been rammed by a Chinese maritime surveillance vessel.

Vietnam and China have for years been embroiled in a dispute over the potentially energy-rich stretch of water, called the East Sea by Vietnam.

“Vietnam demands that China not further complicate the situation in the South China Sea,” Foreign Ministry spokeswoman Le Thi Thu Hang said in a statement.