The Navy on Monday said it has deployed additional naval units to patrol the northern and western sea waters to prevent the illegal entry of migrants, including from India, which could heighten the coronavirus outbreak in the country.

The announcement comes as military personnel apprehended 21 Indian nationals on four Indian boats for allegedly trying to enter the island nation in the last fortnight.

"By virtue of special patrols being conducted in the sea area close to the Palk Strait these days to prevent illegal immigrants from entering Sri Lankan waters, the Navy was able to prevent 11 Indian fishing vessels with 86 individuals, from their suspicious attempt to enter into Sri Lankan waters today (4th May)," the Navy said in a statement.

The patrol was carried out in the sea area south of Mannar, it said.

"Upon informing the Indian High Commission and Indian Coast Guard, arrangements are in place to hand over the 11 Indian fishing vessels and 86 persons to Indian authorities for onward action," the statement said.

Meanwhile, the Navy continues to increase surveillance in northwestern and northern waters to prevent illegal immigrants from entering the country by sea, it said.

The Navy has urged the local fishing community to remain vigilant and refrain from having any contact with foreign fishing vessels at sea and to provide information on any smuggling groups.

For the eight consecutive day on Tuesday, the daily number of coronavirus cases reported in Lanka crossed the 1,000-mark.

The country has recorded several cases of the deadly UK variant.

Health authorities have issued new tough guidelines, including banning wedding receptions and gatherings at religious sites, to prevent the spread of the coronavirus.

According to Johns Hopkins University, the deadly virus has so far claimed 709 lives and infected 113,676 people in the island nation.