Sri Lankan authorities have revised the death toll from Easter Sunday’s string of bombings down to 253 people from the previous estimate of 359.

The country’s director general for health services issued the correction on Thursday, citing the difficulty of identifying victims due to the nature of the bombings, some of which took place in closely confined spaces and left some bodies in pieces.

“The death toll from the Easter Sunday attacks is at least 253, our first estimates were 290 and it will be reduced to 253,” the director-general said in a statement. “Therefore media reports saying that the death toll is 359 are not correct. It should be 253.”

Three churches and three hotels were bombed in quick succession on Sunday morning, with other bombs going off in a private home and near Colombo’s zoo. The precise death counts in each location are still unclear but the bombing of St Sebastian’s church in Negombo, a city north of Colombo, is thought to be the deadliest, killing about 110 people.

The downward revision means the attack is no longer the deadliest ever claimed by Islamic State. A series of coordinated bombings carried out by the group in Baghdad in 2016 killed 340 people, while a bombing and mass shooting claimed by the group at a Sufi mosque in the Sinai desert the following year killed an estimated 311.

The new death toll was the second correction issued by Sri Lankan authorities on Thursday after they released six images and names of people they said were wanted in connection with the terrorist attack – only to retract one who they said was mistakenly identified as a suspect.

The woman who was wrongly named, the Muslim-American activist Amara Majeed, complained on Twitter that she had woken to find her picture on the list. “This is obviously completely false and frankly, considering that our communities are already greatly afflicted with issues of surveillance, I don’t need more false accusations and scrutiny,” she said.

Police said overnight on Thursday a further 16 people were detained for questioning, taking the number held since Sunday to at least 76, including a Syrian national.

Church services have been suspended and mosques have been advised by police not to hold Friday prayers because of the continuing safety risk.