A deadly explosion has rocked a neighborhood in eastern Sri Lanka. It occurred during a gun battle with security forces, tracking suspects from the Easter Sunday bombings. Indian authorities have issued a terrorist alert in southern states, which lie across the strait from Sri Lanka. CGTN's Ravinder Bawa reports.

In the wee hours of Saturday morning, police party reaches the spot to assess the aftermath of explosions and shootout of previous night. In the Eastern town of Kalumunai, fifteen people, including six children, have been killed of which three are of suspected suicide bombers.

CAPTAIN GIHAN SENEVIRATNE SRI LANKA AIR FORCE SPOKESPERSON "The police, the special task force and the Sri Lanka army deployed to the house where the occupants opened fire on the authorities as they came in and explosions were heard at the same time. In the search that followed, the bodies of three male terrorists, three females and six children were found. Three other bodies of suspected terrorists were also found in the vicinity of the house."

Search operations are still going on. In another raid, security forces seized a large cache of explosives, detonators and Islamic State material from a garage in Samanduarai, not very far from Kalmunai. And this could be the lead to the linkage between the local extremist group National Towheed Jammat and IS.

BRIIGADIER SUMITH ATAPATTU SRI LANKA MILITARY SPOKESPERSON "We know there is a link with them, but I just cannot confirm it without proper investigation."

In another search operation in Erakkandi, Trincomalee, the Navy arrested a man with 130 kilos of explosives and 215 detonators. Another suspect was arrested with 49 knives in Maskeliya. Experts say that all the revelations show that the government did not take this threat seriously and now it is a force to reckon with.

FIELD MARSHAL SARATH FONSEKA FORMER SRI LANKA ARMY CHIEF "They not only employ bombs now, they're armed with sophisticated weapons. That indicates they are well organized now and they have combatants and they are terrorists, so we have to take it seriously."

An indefinite curfew was clamped in the affected areas of Eastern province.

RAVINDER BAWA COLOMBO "According to the government sources, these forces are not restricted to the Eastern province but the central and the western province are also affected. They accept that they are a formidable force to deal with. But now they are prepared to take them head on. Ravinder Bawa, CGTN, Colombo."