One week since the deadly blasts in Colombo, Sri Lanka...churches are shuttered and shrouded in sadness.

No masses this Sunday -- for fear bombers could strike again.

Buddhist monks, though, praying for the 250 people who were killed on Easter Sunday, in attacks on churches and hotels.

In what was a peaceful haven and tourist magnet.

Until this week, Islamist militant violence wasn't high on the list of concerns.

So how did it end up seeing the deadliest attack of its kind in South Asia's history?

As Reuters' Joe Brock reports, some are pointing to rifts within Sri Lanka's government and a lack of preparedness by the country's military.

SOUNDBITE (English) REUTERS CORRESPONDENT JOE BROCK, SAYING: "The public here had felt after ten years of peace following the civil war that this was a calm place, where, tourists were welcome and it was a country changed.

Unfortunately, these attacks have instilled fear back into the communities and mistrusts with political leadership.

// Our reporting has uncovered deep rifts between the PM and the President, which laid the groundwork for Islamists to strike." President Maithripala Sirisena has blamed the security establishment -- saying they failed to communicate several warnings they had about the attacks.

But many Sri Lankans say his fallout with the country's prime minister might be at fault too.

Since their relationship deteriorated last year, defense sources tell Reuters the two haven't been sharing security information; with their factions actively trying to undermine each other.

According to civil society groups and western diplomats, Hashim Mohamed Zahran -- the alleged ringleader of the Easter Sunday blasts -- had been flagged to security officials as a threat.

But concerns went largely ignored.

SOUNDBITE (English) REUTERS CORRESPONDENT JOE BROCK, SAYING: "The rebuilding op in the country is going to take months and years.

Security remains tight.

And the situation is tense.

Soldiers are on the streets, police are carrying out raids in many places across the country." All this marks a stark new period for Sri Lanka, which was Lonely Planet's number one travel destination for 2019.

If the military was lethargic, it's wide awake now, and in war mode -- with more than 10,000 soldiers on the streets.