Three churches have been attacked in Sri Lanka as Christians came out to celebrate the resurrection of Jesus at Easter Sunday services.

Three hotels, Shangri-La Colombo, Kingsbury Hotel in Colombo and the Cinnamon Grand Colombo, were also targeted in the attacks.

At least 207 people have been killed and 450 people injured in the attacks, on the holiest day in the Christian calendar.

The churches were located in Kochchikade, Negombo and Batticaloa. 

At least 67 people are reported to have died at St Sebastian's church in Negombo, the BBC reports.

Local media reports say at least 25 people died at the evangelical church in Batticaloa in Eastern Province.

Prime Minister Ranil Wickremesinghe condemned the violence and has ordered the military and police to launch an urgent investigation into the attacks. 

"I strongly condemn the cowardly attacks on our people today. I call upon all Sri Lankans during this tragic time to remain united and strong," he said in a tweet.

"Please avoid propagating unverified reports and speculation. The government is taking immediate steps to contain this situation."

St Sebastian's posted photos of the carnage to its Facebook page showing distressed and injured worshippers and extensive damage to the building.  

No group has come forward yet to claim responsibility.  Police have so far arrested three people in connection with the attacks. 

British Home Secretary Sajid Javid posted a message of solidarity to Twitter following the attacks. 

"Heartbreaking news to wake up to on Easter Sunday," he said.

"These barbaric acts will never succeed in dividing communities. My thoughts and prayers with all those affected. We stand with Sri Lanka and its people." 

The Archbishop of Canterbury, the Most Rev, Justin Welby called the attacks "appalling and dispicable" . 

"Those affected by the appalling and despicable attacks on churches and hotels in Sri Lanka will be in the prayers of millions marking Easter Sunday around the world today," he said. 

"On this holy day, let us stand with the people of Sri Lanka in prayer, condolence and solidarity as we reject all violence, all hatred and all division." 

The Bishop of Lancaster, the Rt Rev Jill Duff, said the attacks were "shocking" and "tragic". 

"May they rest in peace & rise with Him in glory. Of the increase of His government & peace there will be no end," she tweeted. 

Jan Figel, the EU's special envoy for the promotion of freedom of religion or belief, expressed his "deep condolences" for the victims' families.

"Horrible Easter - innocent people/Christians killed by terrorists," he tweeted.