Messages of support and condemnation are pouring in from across the globe following the Sri Lanka attacks.
Australian government agencies are working to find out if any Australians were caught up in deadly blasts.
Australians concerned should call DFAT's Consular Emergency Centre on 1300 555 135 (within Australia) or +61 2 6261 3305 (from overseas).
Religious and world leaders have condemned a series of blasts in Sri Lanka that killed more than 200 people on Sunday, including dozens of foreigners -- with British, Dutch and American citizens believed to be among them.
Hospital sources also said Japanese citizens were among those injured by the bombs which ripped through high-end hotels and churches holding Easter services.
US President Donald Trump on Sunday offered "heartfelt condolences" to the people of Sri Lanka.
"Heartfelt condolences from the people of the United States to the people of Sri Lanka on the horrible terrorist attacks on churches and hotels," he tweeted. "We stand ready to help!"
The US leader erroneously wrote that "138 million people" were killed in the attacks.
British Prime Minister Theresa May described the attacks as "truly appalling".
"The acts of violence against churches and hotels in Sri Lanka are truly appalling, and my deepest sympathies go out to all of those affected at this tragic time," she tweeted.
"We must stand together to make sure that no one should ever have to practise their faith in fear."
"Terrible reports from Sri Lanka about bloody attacks on hotels and churches on this Easter Sunday," Dutch Prime Minister Mark Rutte tweeted after the attacks first emerged.
"Thoughts are with the victims and their relatives."
Pope Francis expressed his sadness over the attacks during his traditional Easter address at the Vatican.
"I want to express my affectionate closeness with the Christian community, attacked while it was at prayer, and to all the victims of such cruel violence," he said.
The Catholic Church in Jerusalem had said in an earlier statement: "We pray for the souls of the victims and ask for speedy recovery of the injured, and ask God to inspire the terrorists to repent of their killing and intimidation."
Prime Minister Scott Morrison said in a statement: "To the beautiful people of Sri Lanka, Australia sends its heartfelt sympathies and our prayers and our support - and our offer to do whatever we can to support you in this terrible time of need.
"At this time as Easter Sunday draws to a conclusion here in Australia, our heart goes out to those Christians and all of those other innocents who have been slaughtered today in this horrific terrorist attack."
A month after dozens of Muslims were killed in a shooting at two mosques in Christchurch, New Zealand Prime Minister Jacinda Ardern described the attack as "devastating".
"New Zealand condemns all acts of terrorism, and our resolve has only been strengthened by the attack on our soil on the 15th of March. To see an attack in Sri Lanka while people were in churches and at hotels is devastating.
"New Zealand rejects all forms of extremism and stands for freedom of religion and the right to worship safely. Collectively we must find the will and the answers to end such violence."
Pakistan's leader Imran Khan offered his "profound condolences" to Sri Lanka.
"Strongly condemn the horrific terrorist attack in Sri Lanka on Easter Sunday resulting in precious lives lost & hundreds injured," he tweeted.
"My profound condolences go to our Sri Lankan brethren. Pakistan stands in complete solidarity with Sri Lanka in their hour of grief."
Narendra Modi, the leader of neighbouring India, said his thoughts are with the bereaved families.
"There is no place for such barbarism in our region," he tweeted. "India stands in solidarity with the people of Sri Lanka."
EU commission chief Jean-Claude Juncker expressed his "horror and sadness" at the blasts, while EU foreign policy chief Federica Mogherini said the attacks marked "a truly sad day for the country and for the world".
"Such acts of violence on this holy day are acts of violence against all beliefs and denominations, and against all those who value the freedom of religion and the choice to worship," she added in a statement.
The US ambassador to Sri Lanka, Alaina Teplitz, tweeted: "Deeply saddened by the senseless attacks in Sri Lanka today. Our thoughts are with the victims and their families. We stand with Sri Lanka's people at this terrible moment."