Flags were lowered to half mast on government buildings, and people bowed their heads and reflected silently on the violence that has caused international outrage.
No group has claimed responsibility for the attacks, which officials said were carried out by at least seven suicide bombers on three churches and four hotels. About 500 people were also wounded.
Daesh's claim, issued on its AMAQ news agency, came shortly after Sri Lanka said two domestic militant groups, with suspected links to foreign militants, were believed to have been behind the attacks at three churches and four hotels, which wounded about 500 people.
The Taliban on Friday announced their annual spring offensive, which comes as the US and Afghan politicians try to negotiate for a peace settlement with the militants.
Abdul Samad Salehi, a provincial councilman, says the convoy was heading to defuse a roadside bomb on Wednesday afternoon when the ambush happened in Anardara district.
An Afghan official says the Taliban have targeted security checkpoints in northeastern Takhar province, killing eight members of the security forces.
Palestinians attended funerals and extricated bodies from collapsed buildings. There was no official word from Israel on any bargaining behind the ceasefire.
Wreckage of vehicles littered the pavement near the shrine as first responders rushed to the scene and armed security forces fanned out in the area.
"As we crossed the road a blast took place in front of us," witness Ritat Shahid told AFP.
A second overnight curfew imposed nationwide ensured there was no repeat of Monday's violence against Muslims, who make up some 10 per cent of Sri Lanka's population of 21 million.
The shootout between troops and suspected militants erupted on Friday evening in Sainthamaruthu in Ampara district, to the south of the town of Batticaloa, site of one of the Easter Sunday blasts at three churches and four luxury hotels.