
Sri Lanka fell silent for three minutes today on a day of national mourning to honour those killed in suicide bomb blasts on Easter Sunday as the death toll rose to 321.

The silence began at 8.30am to mark the time the first bomb detonated while flags were lowered to half mast on government buildings, and liquor shops were ordered closed for the day.

Mass burials also took place at St Sebastian's Church in Negombo, one of those targeted during the attack, as thousands of people gathered to pay their respects.

Sri Lankans honoured their dead as ISIS claimed responsibility for the attack which investigators believe was in 'retaliation' for the New Zealand mosque shootings.

Mass funerals for the victims of the Easter Sunday bombings in Sri Lanka began taking place on Tuesday as the death toll was raised to at least 321, including 45 children

Coffins were laid into shallow graves at a cemetery near St. Sebastian Church in Negombo, Sri Lanka, which was among those targeted by the bombers two days before

Sri Lankans prepare to bury the coffins carrying remains of Berington Joseph, left, and Burlington Bevon, who were killed in the Easter Sunday bombings in Colombo, Sri Lanka

Six near-simultaneous attacks on three churches and three luxury hotels in Sri Lanka left at least 321 dead with hundreds more wounded in hospital in the island's deadliest violence in a decade (pictured, funerals take place for victims)

Emotions ran raw at the funeral services while across the nation a three-minute silence was held from 8.30am, the time of the first bomb blast, and flag were lowered to half-mast on government buildings

A woman collapses on to the grave of her loved one during mass funerals for the victims of the Easter Sunday bomb attacks

The funerals began taking place despite the archbishop of Sri Lanka warning churches to delay the ceremony for fear of further attacks being carried out

Sri Lankan Christians offer prayers as two of the victims of Sunday's bomb attack are buried near the capital Colombo

'The preliminary investigations have revealed that what happened in Sri Lanka [on Sunday] was in retaliation for the attack against Muslims in Christchurch,' state minister of defence Ruwan Wijewardene told parliament.

White supremacist Brenton Tarrant allegedly slaughtered 50 worshippers at two mosques in the New Zealand city of Christchurch on March 15 while live-streaming the shooting on Facebook.

Among those being buried on Tuesday was Berlington Joseph who was killed during prayers along with his five sons, the youngest of which was just 11 months old.

In Negombo, an elderly man wept uncontrollably by the coffin bearing the body of his wife, while relatives of other victims stood aghast and silent.

Coffins were carried into the church grounds one-by-one for services, and then to a newly established cemetery on church land.

'It's beyond words,' said Father Suranga Warnakulasuriya, who had come from another parish to help conduct funerals. 'It's very hard to bear. For me it is very difficult, so imagine how hard it is for the loved ones.'

This morning, Sri Lankan investigators revealed they now believe two domestic Islamist organisations - including the National Thowheed Jamaath (NTJ) - were behind the co-ordinated blasts which killed at least 45 children.

The NTJ were the subject of an intelligence warning ten days before the attacks, raising questions about why more precautions were not taken.

Wijewardene named another local group, Jamaat-ul-Mujahideen India (JMI), as being responsible. Little is known about JMI, other than reports it was established last year and is affiliated to a similarly named group in Bangladesh.

Police are now on the hunt for a lorry and a van both believed to be carrying explosives around the capital Colombo, reports News 1st.

The government also imposed a state of emergency for the first time since the country's civil war, giving police and the military special powers including the ability to arrest suspects without a court order.

The news comes as Cardinal Malcolm Ranjith, the archbishop of Sri Lanka, warned churches to delay memorials services in case of further attacks.

Sri Lanka held a three-minute nationwide silence at 8.30am this morning - the same time the first of six bombs detonated on Sunday morning killing at least 321 people, including at least 45 children

Investigators believe that attack was 'retaliation' for the Christchurch mosque shootings in which 50 Muslims were slaughtered. Pictured: flowers at a memorial for the victims of the New Zealand shootings

White supremacist Brenton Tarrant allegedly slaughtered 50 people at the Al-Noor Mosque and the Linwood Mosque while live-streaming the attack on Facebook. Pictured: one of the people injured in the New Zealand attacks as they are taken to hospital

Konsi Vinifrieda, 62, mourns the death of her 27-year-old granddaughter Hirsushi Kansika before her funeral in Katuwapity village

A woman fainted while praying for the victims of the Easter Sunday attacks in the country's capital Colombo earlier today

Burials for the dead began today in Negombo, pictured. The attacks have sparked local and international outrage, and have been condemned by Sri Lankan Muslim groups

Pictured: relatives mourning beside the coffin of one of the suicide bomb victims at St Sebastian's Church in Negombo

Flags were lowered to half mast on government buildings, and people bowed their heads and reflected silently on the violence that has caused international outrage.

The silence began at 8.30am, the time that the first of six bombs detonated on Sunday morning, unleashing carnage at high-end hotels and churches packed with Easter worshippers.

Wijewardene has blamed 'weakness' within Sri Lanka's security apparatus for failing to prevent the nine bombings.

'By now it has been established that the intelligence units were aware of this attack and a group of responsible people were informed about the impending attack,' he said. 'However, this information has been circulated among only a few officials.'

Wijewardene also said the toll from coordinated bombings at churches, luxury hotels and other sites now stands at 321 people dead and 500 injured, with several people dying of their injuries overnight.

'The total now is 45 children who died,' UNICEF spokesman Christophe Boulierac told reporters in Geneva, stressing that others 'are wounded and are now fighting for their lives,' meaning the toll among minors from the Sunday attacks could rise.

The first memorial services for the victims, among them dozens of foreigners, were being held today, hours after the government imposed a state of emergency.

At St Anthony's Shrine in Colombo - where scores died as they gathered for Easter Sunday prayers - a few dozen people held candles and prayed silently, palms pressed together.

And at St Sebastian's Church in Negombo, north of the capital, an elderly man wept uncontrollably by the coffin bearing the body of his wife. More than 1,000 mourners gathered at the church where more than 100 parishioners were killed.

Cardinal Malcolm Ranjith, the archbishop of Sri Lanka who led the service, urged other churches to delay memorials amid fears that more bombers may be at large.

'The security forces have not cleared the situation yet ... there could be more attacks on public gatherings,' he told reporters.

'I urge priests to not conduct any services at churches until I notify.'

Police said that 40 people were now under arrest over the suicide bomb attacks - the worst atrocity since Sri Lanka's civil war ended a decade ago.

Flags were lowered to half mast on government buildings, and people bowed their heads and reflected silently on the violence that has caused international outrage

Police have said that at least 310 people have been killed, with another 500 injured. Anthony Jayakody, auxiliary bishop of Colombo said: 'There are so many bodies that we can't accommodate them all at once'

Pictured: a man weeps as his walks behind the coffin of one of the victims of the blasts on Easter Sunday

The suicide bombers hit three Colombo luxury hotels popular with foreign tourist and three churches: two in the Colombo region and one in the eastern city of Batticaloa. Pictured: a woman cries next to a coffin of one of the victims

The government has said the National Thowheed Jamaath (NTJ), a little-known Islamist group, was behind the violence, but said they believed the organisation had international help

More than 1,000 mourners gathered at the St. Sebastian church in Negombo, where more than 100 parishioners were killed as they worshipped on Sunday morning

Police said that 40 people were now under arrest over the suicide bomb attacks - the worst atrocity since Sri Lanka's civil war ended a decade ago

The attacks were also the worst ever against the country's small Christian minority, who make up just seven percent of the 21 million population.

Investigators are now hunting for clues on whether the local Islamist group named as the chief suspect - National Thowheeth Jama'ath (NTJ) - received 'international support', said cabinet minister and government spokesman Rajitha Senaratne.

He said it was not possible for such 'a small organisation' to carry out such well co-ordinated suicide strikes.

President Maithripala Sirisena's office said there was intelligence that 'international terror groups' were behind the local perpetrators and that he would seek foreign help to investigate.

The state of emergency, which gave police and the military special powers to counter militant strikes, came into force at midnight. Suspects can be detained without a court order.

A second straight night-time curfew was also put in place, but lifted before dawn.

Officials are 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 NTJ planned suicide attacks on churches.

Spokesman Senaratne said the warning was not passed on to Prime Minister Ranil Wickremesinghe or other top ministers.

Tensions remained high and security heavy after a bomb discovered by police on Monday near one of the targeted churches blew up before police could defuse it. Although there was a powerful blast, no injuries were reported.

Police also found 87 bomb detonators at a Colombo bus station.

A priest administrates a burial ritual for one of the bomb victims who is being laid to rest in a mass grave in Negombo

Pictured: a member of the clergy walks between coffins during a mass funeral at St Sebastian Church

Officials are 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 NTJ planned suicide attacks on churches

Ethnic and religious violence has plagued Sri Lanka for decades, with a 37-year conflict with Tamil rebels followed by an upswing in recent years of clashes between the Buddhist majority and Muslims. Pictured: relatives mourning during a mass funeral

More details have begun to emerge about some of the foreigners killed in the blasts.

The United States reported at least four Americans killed - including a child - and the Netherlands raised their toll to three.

Danish billionaire Anders Holch Povlsen lost three of his children in the attacks, a spokesman for his company said.

Eight Britons, eight Indians and nationals from Turkey, Australia, France, Japan and Portugal, were also killed, according to Sri Lankan officials and foreign governments.

The suicide bombers hit three Colombo luxury hotels popular with foreign tourists - the Cinnamon Grand, the Shangri-La and the Kingsbury - and three churches: two in the Colombo region and one in the eastern city of Batticaloa.

Two additional blasts were triggered as security forces carried out raids searching for suspects.

Interpol said it was deploying investigators and specialists to Sri Lanka, and the US State Department warned of possible further attacks in a travel advisory.

Ethnic and religious violence has plagued Sri Lanka for decades, with a 37-year conflict with Tamil rebels followed by an upswing in recent years of clashes between the Buddhist majority and Muslims.

Burials were expected to begin for some of the dead on Tuesday.

At St Sebastian's, the atmosphere was heavy with grief as coffins were brought in the grounds one at a time for services.

'There are so many bodies that we can't accommodate them all at once,' Anthony Jayakody, auxiliary bishop of Colombo, told AFP.

The attacks have sparked local and international outrage, and have been condemned by Sri Lankan Muslim groups, with one urging the 'maximum punishment for everyone involved in these dastardly acts'.