Sri Lanka: Colombo on high alert following reports of explosives-laden van

All police stations in Sri Lanka's Colombo were put on high alert as police were hunting for an unidentified container truck and a van, believed to be carrying explosives, PTI reported.

A warning issued by the Director of Security at the Colombo Harbour said intelligence had found information that an unidentified container truck and a van carrying a potentially explosive device was heading towards Colombo.

Search operations are currently underway at the Colombo Harbour for the potential threat.

On Sunday, multiple blasts ripped through Sri Lanka's churches and luxury hotels killing over 300 people. About 500 were also injured.  The attacks are being billed as the worst-ever in the history of the island nation after the civil war that ended almost a decade ago. 

The security alert came as the island nation observed a day of national mourning for the victims of the attack.

In security measures, Sri Lanka has imposed a state of emergency hours after officials blamed local Islamist group for the attacks.

The state of emergency, which gives police and the military special powers to counter militant strikes, came into force at midnight.

Suspects can be detained without any court order under emergency.

Officials are also investigating why more precautions were not taken after an April 11 warning from Sri Lanka's police that a "foreign intelligence agency" had reported the National Thowheed Jamath (NTJ) planned suicide attacks on churches. 

(With inputs from news agencies)