Suspected Sri Lankan bomber Moulvi Zahran Hashim pledging allegiance to IS

The purported leader of an Islamic extremist group blamed for a terror attack in Sri Lanka that killed over 300 people began posting videos online three years ago calling for non-Muslims to be 'eliminated,' faith leaders said Tuesday.

Zahran Hashim, the chief suspect behind the Easter Sunday bombings, also called for those who disagreed with Islam to be killed in videos widely available on YouTube.

It was also revealed that foreign intelligence agencies warned of attacks by the group several times in recent weeks – the first as early as April 4 – but that the information was not passed higher up the chain of command.

Much remained unclear about how a little-known group called National Thowfeek Jamaath carried out six large near-simultaneous suicide bombings striking churches and hotels.

However, warnings about growing radicalism in this island nation off the coast of India date to at least 2007, while Muslim leaders say their repeated warnings about the group and its leader began around three years ago.

Despite their pleas, there was no visible reaction from officials responsible for public security, the leaders said.

'Some of the intelligence people saw his picture but they didn't take action,' said N.M. Ameen, the president of the Muslim Council of Sri Lanka.

Hilmy Ahamed, the Muslim council's vice president, spoke about one of Hashim's online speeches, saying: 'It was basically a hate campaign against all non-Muslims.

'Basically, he was saying non-Muslims have to be eliminated.'

Hashim, the suspected mastermind of the Sri Lanka bombings, was flagged to security services because of online rants calling for non-Muslims to be killed

Zahran's name was on one intelligence warning shared among Sri Lankan security forces, who apparently even quietly took their growing concerns to international experts as well.

Anne Speckhard, the director of the International Center for the Study of Violent Extremism, said a Sri Lankan intelligence official approached her at a conference in February with a surprising question.

She was worried about what she described as a violent, homegrown jihadi group that 'would just disappear' when the government tried to crackdown on them.

'The intel person kind of came up to me and said, "You know, we're kind of worried about this new group and there's some activity going. What do you think?'' Speckhard told The Associated Press on Tuesday.

'It just kind of blows my mind that's who it was.'

As far as the planning, Speckhard noted that Sri Lanka was 'a part of the world that developed suicide vests' during the civil war against the Tamil Tigers, a secular, nationalist group that once was the world's top suicide attacker.

But the style of the attack, targeting churches on Easter and hotels frequented by foreigners, followed that of al-Qaida and the Islamic State group.

'It is a simple attack that is well-thought out,' Speckhard said. 'I do believe well-thought out is a product of being in touch with someone from the outside.'

That's a feeling shared by the Austin, Texas-based private intelligence firm Stratfor.

'The degree of sophistication in the making of the bombs indicates that the attackers did in fact have help from outside Sri Lanka, which could have come via coordination with external militant groups such as al-Qaida or the Islamic State, from Sri Lankan fighters returning from battlefields in Iraq and Syria, or from a combination of the two,' a Stratfor analysis Tuesday said.

'Clarity on the nature of such networks, however, will have to wait for the emergence of more details about the attacks.'

Moulvi Zahran Hashim, the founder of NTJ who referred to himself as Abu Ubaida, was named as the alleged mastermind behind the Easter Sunday suicide bombings in churches and luxury hotels that killed 320 people and injured hundreds more.

The first mass funerals took place for victims of the bombings on Tuesday, as officials raised the death toll to 310, with hundreds more wounded

Grieving relatives watch as workers place the coffin of a bomb blast victim into a grave during a burial ceremony at a cemetery in Negombo

Sri Lankan mourners take part in a silence in tribute to bomb blast victims in Colombo

Local media claimed the extremist preacher, who had pledged allegiance to Islamic State, was one of the bombers who attacked the Shangri-La Hotel in Colombo, but this was later disputed.

Hilmy Ahamed, vice-president of the Muslim Council of Sri Lanka, said he warned military intelligence officials about the group and its leaders.

Speaking from Colombo, Mr Ahamed said: 'Targeting the non-Muslim community is something they encourage – they say you have to kill them in the name of religion.

'I personally handed over all the documents three years ago, giving names and details of all these people. They have sat on it. That's the tragedy.'

Meanwhile CCTV footage emerged of an unidentified bomber entering St Sebastian's Church at Katuwapitiya. Wearing sunglasses and sandals, the man was seen casually walking past worshippers just moment before he is believed to have blown himself up.

Concerns have been raised that a bitter split among senior politicians led to vital intelligence before the NTJ attacks being wasted as key figures were not alerted.

Tensions between president Maithripala Sirisena, who heads the security forces, and prime minister Ranil Wickremesinghe are high following Sirisena's sacking of the PM in October, which triggered a weeks-long political crisis that ended only when the Supreme Court overturned the decision.

Yesterday Mr Wickremesinghe acknowledged that 'information was there' about possible attacks.

Sri Lanka's minister of telecommunications, Harin Fernando, yesterday circulated an internal security memo dated earlier this month that warned NTJ was 'getting ready for suicide attacks on popular Catholic churches and the Indian High Commission'. It also said NTJ members were 'inciting hatred' among online followers. 'Serious action needs to be taken as to why this warning was ignored,' Mr Fernando said.

Sri Lanka's health minister Rajitha Senaratne revealed that on April 9 the defence ministry wrote to the police chief with intelligence that included NTJ's name, and, on April 11, police warned the heads of security of the judiciary and diplomatic security division.

Mr Senaratne called on the inspector general of police to resign for failing to act on the intelligence reports. He said: 'The intelligence services had done the work, but it was not acted on at higher levels.

Seven suicide bombers killed at least 320 people in coordinated attacks on five-star hotels and churches on Easter Sunday. Pictured: the interior of St Sebastian's church in Negombo

A crime scene official inspects the site of a bomb blast inside a church in Negombo, Sri Lanka, which lost half its roof tiles with the force of the blast

'Unfortunately, despite all these revelations by the intelligence units we could not avert these attacks,'

CNN reported that NTJ leader Hashim wanted to attack the Indian High Commission in Colombo on April 4, but it was thwarted.

UK sources said the Muslim Council of Sri Lanka made a complaint to authorities specifically about a 'hate speech video' by Hashim. It came as footage was posted of a rant by the preacher on YouTube in which he issued threats against 'infidels'. Chillingly, the flags of countries such as Britain, the US and Portugal – all countries that suffered casualties in the bombings – were shown in the background in flames.

Footage also emerged of what is believed to be a gun-toting Hashim standing in front of an Islamic State flag.

Sri Lankan people run for safety as authorities announced an evacuation of the area after a van was found parked with a suspected explosive device near St Anthony's Church in Kochchikade, Colombo

Sources said Sri Lanka's intelligence services are now probing the possibility that the bomb maker was from outside the country or had received foreign training because of the sophisticated nature of the devices.

Just weeks ago police found 220lb (100kg) of high-powered C4 explosives, a cache of dozens of detonators, a stock of cords, light bulbs and cans of nitrate acid – banned in Sri Lanka – which police linked to terrorists.

The explosives and bomb-making equipment were buried in barrels on a coconut estate in Puttalam, 85 miles north of Colombo and 65 miles from Negombo, two of the major targets of the atrocity. The barrels appeared to have originated in India.

Manisha Gunasekera, the High Commissioner of Sri Lanka to the UK, said the government was investigating any security 'lapses'.

She told BBC 5 Live: 'There is an investigation that has been launched by the Sri Lankan government with regard to this information that there may have been intelligence available prior to this incident.

Blood stains are seen on the wall and on a Jesus Christ statue at the St. Sebastian's Church after blast in Negombo, north of Colombo, Sri Lanka,after the bombing

'They are also looking into the authenticity of documentation that may be made available in this regard.

'Once the investigation is concluded this will shed more light on whether there were any lapses on the part of the law enforcement authorities or any other entities.'

The Council of Sri Lankan Muslim Organisations in the UK (Cosmos) last night condemned the attacks and called for an investigation into the 'unforgivable disaster'.

In a statement, Cosmos said: 'This series of co-ordinated terror attacks on this holy day for Christians targeting innocent civilians in churches and other locations clearly shows that it is a part of a greater machination, to bring further disaster to Sri Lanka, thus bringing back ugly memories of the bloody war which engulfed the nation for over three decades.

'The gravity of this despicable spate of terror attacks is so acute that the aspirations of the people of Sri Lanka to live in a peaceful and an inclusive Sri Lanka appears to be challenged as never before.'