Soldiers stand guard at the Bandaranaike International Airport in Colombo, Sri Lanka, April 22, 2019. The death toll from the multiple blasts that ripped through Sri Lanka on Sunday rose to 228 while 450 others were injured, local media quoting hospital sources said. (Xinhua/Wang Shen)

COLOMBO, April 21 (Xinhua) -- The death toll from the multiple blasts that ripped through Sri Lanka on Sunday rose to 228 while 450 others were injured, local media quoting hospital sources said.

The Sri Lanka Tourism Development Authority said in a statement that 32 foreigners from China, the United States, Britain and Belgium were among those killed.

Police said seven suspects were arrested over the blasts and investigations into the explosions were underway.

Police spokesperson SP Ruwan Gunasekara said security was beefed up across the island country and an indefinite nationwide curfew was imposed.

Police recovered a vehicle which was used by one of the suspects to transport the explosives in the capital, Gunasekara said.

State Minister of Defense Ruwan Wijewardene said almost all the bombings in Colombo were carried out by suicide attackers belonging to "extremist groups."

Police said they could not divulge who was behind the attacks at the moment.

Eight explosions were reported from across Sri Lanka on Sunday as hundreds of worshippers gathered at churches to commemorate Easter Sunday.

Gunasekara said explosions were reported from St. Anthony's Church in Kochchikade in the capital of Colombo and another one from St. Sebastian's Church in Negombo, on the outskirts of Colombo on Sunday morning.

A third explosion was reported from the Zion Church in the eastern town of Batticaloa.

Blasts also struck three high-end hotels in Colombo - Cinnamon Grand, Shangri-La and Kingsbury hotels, while on Sunday afternoon an explosion was reported from a hotel opposite a zoo in Dehiwala in Colombo and another from a housing complex in Dematagoda, also in the capital.