Pictures from inside one of the churches show rubble across the floor. [Source: St Sebastian Church / Facebook

Hundreds of people are reportedly injured and many are feared dead after a series of explosions blasted across Sri Lanka.

St Anthony’s Church in Colombo and the St Sebastian’s Church in Katana were both targeted during their Easter mass, police sources told media outlet AFP.

In the chaotic aftermath of the explosions, St Sebastian’s Church shared an urgent appeal for help on its Facebook page.

“A bomb attack to our church – please come and help if your family members are there,” it wrote.

The Facebook post includes photos which appear to be from inside the church, showing rubble scattered across the floor and people bloodied with injuries.

It’s believed at least 480 have been injured in the various blasts across the country, with the number expected to rise. Local media report the unofficial death toll as 25, but that is also expected to rise.

The first explosion hit St Anthony’s Church around 8:45am on Sunday (local time) as the Easter Mass took place, according to local journalist Roel Raymond.

She told Newshub it’s one of the main Catholic churches in Colombo.

Minutes later, another explosion ripped through St Sebastian’s Church and the Zion Evangelical Church in Batticaloa, before three hotels were reportedly attacked – the Kingsbury Hotel, Shangri-la Hotel and Cinnamon Grand Hotel in Colombo.

According to a Sri Lanka security official, the explosions were near-simultaneous blasts, Sky News reports.

It’s expected authorities will place a curfew in the aftermath of the explosions, to prevent civilians from travelling around, Raymond said.

The blasts follow an attack last Sunday, where a Methodist church in Anuradhapura was targeted. Authorities told the church not to allow worshippers from other villages to visit after the attack.