Masked men opened fire on the bus, killing six policemen escorting the Sri Lankans and a driver.
Seven players and an assistant coach were wounded. The team later flew back to Sri Lanka.
There is no word on the identities or motives of the gunmen, who escaped.
Residents in Lahore converged on Liberty Square on Wednesday to pay homage to the policemen killed in the attack, holding prayers and laying wreaths.
Mr Zardari has said that progress is being made on finding the gunmen.
He assured visiting Sri Lankan Foreign Minister Rohitha Bogollagama in Islamabad that "progress has been made in the investigation and the perpetrators will be exposed and brought to justice".
But Mr Zardari admitted that the attack was "a serious setback that had also undermined the sport of cricket in Pakistan".
The BBC's M Ilyas Khan in Islamabad says hundreds of people have been questioned in poorer areas of Lahore to find clues to the attackers.
A number of people have been detained for further investigation but senior police official Haji Habibur Rehman told the Associated Press news agency that little headway had been made in identifying the men.
Chris Broad says he is 'angry' about the lack of security
Meanwhile, ICC match referee Chris Broad, who was in the bus when it came under fire, has accused Pakistani security forces of "vanishing" during the attack.
He said he had raised concerns about security before the team travelled to Pakistan but had been promised high level security protection.
Video footage shot during the attack showed "terrorists shooting past our van, sometimes into our van - and not a sign of a policeman anywhere," said Mr Broad.
"They had gone, left the scene, and left us to be sitting ducks.
"I am extremely angry that we were promised high-level security and in our hour of need that security vanished."
Mr Broad's claims were strongly denied by Ijaz Butt, chairman of the Pakistan Cricket Board, who referred to the policemen killed by the attackers.
The attacks are expected to have massive ramifications for the cricket world.
The ICC is considering whether Pakistan can co-host the cricket World Cup, due to be held across four South Asian countries in 2011.
Pakistan had invited Sri Lanka to tour only after India's cricket team pulled out of a scheduled tour following the Mumbai attacks.
But Sri Lankan Foreign Minister Rohitha Bogollagama said his country did not rule out a future visit to Pakistan by their cricket team.
"We don't want to see Pakistan getting isolated in the cricketing world," he said.
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