It said on its website that no vessel is allowed to enter the area in the South China Sea, which Vietnam calls the East Sea, when the drills are underway.

The action comes amid the international community’s concern over China's recent actions in the South China Sea.

The country has been ramping up its aggressive behavior in the waters since the start of this year while other countries have been focused on combating the Covid-19 outbreak.

It has created the so-called "Xisha" and "Nansha" districts on Vietnam’s Hoang Sa (Paracel) and Truong Sa (Spratly) Islands, sunk Vietnamese fishing vessels off the former, unilaterally issued a fishing ban and sent a ship to harass a Malaysian oil and gas exploration vessel.

It recently announced a vegetable farming project on Woody (Phu Lam) Island in the Paracels to strengthen its illegal claim. It has sent two diplomatic notes to the United Nations to make the infamous Four Sha claim, which covers a broader range of water than its illegal nine-dash line.

At the 36th ASEAN Summit in Hanoi last Friday regional leaders expressed concern over recent South China Sea developments and called on all parties to build trust.

Vietnam called for a resumption of negotiations between ASEAN and China on the Code of Conduct of Parties in the South China Sea (COC).

Prime Minister Nguyen Xuan Phuc said at the summit that the Covid-19 pandemic had disrupted the discussions on the COC between ASEAN and China, which have been ongoing since 2002 for developing legally binding rules.

Vietnam's Foreign Affairs Ministry has said repeatedly that all activities of parties in the Truong Sa and Hoang Sa Islands without Vietnam's permission are invalid.

It said Vietnam has full legal basis and historical evidence to assert its sovereignty over the islands, as well as rights over its waters in accordance with the United Nations Convention on the Law of the Sea (UNCLOS).

China had seized the Paracel Islands from South Vietnam by force in 1974, and has been illegally occupying it since.