Earlier Pakistani officials said that more than 100 people had been detained as investigators hunted for the attackers, who calmly walked away from the scene after ambushing the Sri Lankan team's bus as they travelled to the city's Gaddafi stadium.
A reward of $125,000 has been offered for help in finding those behind Tuesday's attack.
"We also have some important leads that would eventually unearth people responsible for this terrible act," Shah Mehmood Qureshi, Pakistan's foreign minister, said during a news conference with his Sri Lankan counterpart in Islamabad.
No one has claimed responsibility for the attack but speculation has largely focused on homegrown groups such as Lashkar-e-Taiba, which India has blamed for last year's attack on Mumbai, Laskhar-Jhangvi and the so-called Pakistani Taliban.
However, some people in Pakistan have suggested the assailants may have crossed from India or co-operating with Sri Lanka's Liberation Tigers of Tamil Eelam (LTTE) rebels.
"LTTE definitely, we believe have outside links and international connections to other terrorist organisations but these are matters that we cannot discuss in the open," Rohitha Bogollagama, the Sri Lankan foreign minister, said.
In an opinion piece in the Wall Street Journal on Wednesday, Asif Ali Zardari, the Pakistani president, said "failure is not an option" in the battle against the perpetrators of such acts of violence.
"This is an existential battle. If we lose, so too will the world," he said.
Tuesday's attack "shows once again the evil we are confronting", Zardari said.
'State of war'
Rehman Malik, the interior ministry adviser, declared the country to be "in a state of war", but told Pakistanis: "Be patient, we will flush all these terrorists out of the country."
He did not rule the role of a "foreign hand" in the attack.
Seven Sri Lankan players and an assistant coach were among the 19 wounded in the attack on Tuesday.
Two members of the Sri Lankan team, Thilan Samaraweera and Tharanga Paranavitana, were sent to hospital but later released.
They have since arrived back in the Sri Lankan capital, Colombo, to an emotional welcome from relatives.
Sri Lanka's cricketers were invited to play in Pakistan after India pulled out of a scheduled test match over security concerns.
New Zealand on Wednesday indicated it would call off its November tour of Pakistan, and the International Cricket Council raised doubts whether the country could still co-host the 2011 World Cup.
"I don't think any international team will be going to Pakistan in the foreseeable future," Justin Vaughan, chief executive of New Zealand, said.