Police spokesman Ruwan Gunasekera has reportedly said that around 500 people were wounded in the blasts, adding that 40 people were now under arrest in connection with the attacks, which Sri Lanka 's government has blamed on the local Islamist group National Thowheeth Jamaath.

The death toll from a series of suicide bomb attacks in Sri Lanka has risen to 310, with several people dying of their injuries overnight, a police spokesman said Tuesday as cited by AFP.

The number of people killed in a series of deadly blasts that hit Sri Lanka on Sunday has risen to 310, local media reported on Tuesday.

According to previous reports, 290 people were killed and 500 were injured in the explosions.

The News 1st local media outlet reported that the number of those wounded in the attacks now stands at 480.

Meanwhile, three minutes of silence have been observed across Sri Lanka to pay tribute to all those killed in Sunday’s terrorist attacks, in line with a full day of national mourning on Tuesday.

This comes after Sri Lankan Economic Reforms and Public Distribution Minister Harsha De Silva told CNN that the Sunday attacks were not a flop of the country's intelligence services but a failure to circulate information internally to people capable of taking action.

"There was a colossal failure in the communication of this intelligence to the right people who could have taken measures to prevent at least some of what happened," De Silva told CNN on Monday.

Earlier, Sri Lanka 's Health Minister Rajitha Senaratne said that the bombings were organised by the local group National Thowheed Jamaath (NTJ) and that they had been carried out with help of a vast international network.

Eight explosions took place in Sri Lanka on the Easter Sunday, with three churches and three hotels having been targeted. These are the worst attacks in the country's modern history since the end of the 25-year-old civil war. 

A massive security operation was launched following the attacks, with at least 24 people already detained in connection with the bombings. Sri Lanka’s authorities introduced and re-introduced curfews, deploying an extra 1,000 troops in the capital Colombo.