Sri Lanka puts all police stations in Colombo on high alert following reports of lorry, van carrying explosives

Sri Lanka on Tuesday placed all police stations in Colombo on high alert as police were hunting for an unidentified container truck and a van, believed to be carrying explosives. 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 potential explosive device was heading towards Colombo.

Search operations are currently underway at the Colombo Harbour for the potential threat. The alert came as the island nation observed a day of national mourning for over 320 people killed in a series on blasts on Easter Sunday.

Meanwhile, the Islamic State on Tuesday claimed responsibility for a series of devastating suicide attacks that killed 321 people and wounded more than 500 others. "Those who carried out the attack that targeted members of the US-led coalition and Christians in Sri Lanka the day before yesterday are Islamic State group fighters," the terror group said in a statement through its propaganda 'Amaq' news agency, according to the Site Intelligence Group, which monitors jihadist activities.

Seven suicide bombers carried out multiple blasts that tore through three churches and three luxury hotels in Sri Lanka on Easter Sunday, killing.

Forty suspects, including the driver of a van allegedly used by the suicide bombers, have been arrested in connection with the attacks which shook Sri Lanka. Government's spokesman Rajitha Senaratne said local Islamist extremist group called the National Tawheed Jamath (NTJ) is suspected of plotting the blasts.

"All suicide bombers involved in the blasts are believed to be Sri Lankan nationals," said Senaratne, who is also the Health Minister.