"All activities on Vietnam’s Hoang Sa (Paracel) and Truong Sa (Spratly) islands without Vietnam’s approval are violations of Vietnam’s sovereignty over the islands. They complicate the situation and are not beneficial for bilateral relations, peace, stability, order, security, safety and freedom of navigation in the air and on sea in the East Sea," Foreign Ministry spokeswoman Le Thi Thu Hang said Thursday.

She was responding to inquiries about China’s illegal drill on Triton Island, part of the Paracel Islands.

The East Sea is known internationally as the South China Sea.

Hang reiterated that Vietnam has full legal basis and historical evidence under international law to assert its sovereignty over both archipelagos.

On March 3, Chinese state broadcaster China Central Television (CCTV) aired a documentary wherein its army forces participated in an illegal drill on Triton Island. Air-cushioned landing crafts, tanks, aircrafts and armed soldiers were shown.

The broadcaster said the drill was to explore the tactics and methods of joint warfare, but did not specify an exact date. Observers said the drill happened recently.

The Chinese army announced the drill on March 1 amid rising tension in the East Sea and the Taiwan Strait. It said a month-long drill had begun near the Leizhou Peninsula.

China has followed up on its illegal claim to most of the East Sea with repeated transgressions, including activities like creating artificial islands and militarizing maritime features, ignoring objections from both Vietnam and the international community.