Yousuf Raza Gilani, the Pakistani prime minister, swiftly condemned the incident, saying it had "humiliated the country" while Rehman Malik, the head of the interior ministry, declared Pakistan to be "in a state of war".
The Sri Lankan government also condemned the assault as "cowardly" and said it was immediately dispatching the country's foreign minister to Pakistan.
No-one has so far claimed responsibility for the attack.
Officials said that in addition to the wounded players Paul Farbrace, the team's assistant coach, and Brenden Kurrupu, the manager, were also hurt.
Pakistani air force helicopters later took the Sri Lankan cricket team - including two players on stretchers - from the Gaddafi Stadium in Lahore, where the match was held, to an air base.
They have since arrived back in the Sri Lankan capital, Colombo, to an emotional welcome from relatives.
Thilan Samaraweera and Tharanga Paranavithana, two of the injured players, were taken to a private medical facility in Colombo, officials told AFP.
In Lahore the city's police chief, Haji Habibur Rehman, said there were about 12 attackers, who "appeared to be well-trained terrorists".
"Five policemen who were providing protection to the team sacrificed their lives," he said.
Earlier television footage had shown the attackers firing at the convoy as they retreated from the scene, along with several damaged vehicles and a unexploded grenade lying on the ground.
Security experts also defused two car bombs near the scene and recovered a stash of weapons including grenades, 3kg of explosives, a pistol and a detonating cable after the deadly ambush, the AFP news agency reported.
|Six police officers escorting the Sri Lankan team were killed [Reuters]
Sri Lanka's cricketers were invited to play in Pakistan after India pulled out of a scheduled test match over security concerns.
It was unclear who was behind Tuesday's assault, and no one has yet claimed responsibility, however Pakistan has seen a wave of violence in recent years, and some foreign sports teams have refused to play in the country because of security worries.
Sri Lanka has also seen attacks in the country's north and in the capital Colombo as government forces claim to be on the verge of crushing the Liberation Tigers of Tamil Eelam (LTTE) after decades of civil war.
Authorities said they were investigating possible links to the LTTE, but military officials in Sri Lanka said they did not believe the group was responsible for the Lahore attack.
The International Cricket Board denounced the Lahore attack.
"We note with dismay and regret the events of this morning in Lahore and we condemn this attack without reservation," Haroon Lorgat, the board's chief executive, said in a statement.
The Punjabi governor, meanwhile, likened the shooting to the attacks in the Indian city of Mumbai last year in which 179 people were killed when armed men opened fire at luxury hotels and the main railway station.
"I want to say it's the same pattern, the same terrorists who attacked Mumbai," Taseer said.
"They are trained criminals. They were not common people. The kind of weaponry they had, the kind of arms they had, the way they attacked ... they were not common citizens, they were obviously trained."
Laskhar-e-Taiba, the group blamed for the Mumbai attack, originates in Pakistan's Punjab province, of which Lahore is the capital.
The attack also comes amid a backdrop of political instability in the province.
Supporters of Nawaz Sharif, the leading opposition politician, have been protesting daily in Punjab against a supreme court ban on Sharif and his brother from standing for election.
The provincial government, which was led by Sharif's party, has been dismissed by Asif Ali Zardari, Pakistan's president, and federal rule imposed.
Hamid Mir, a Pakistani journalist and political analyst, blamed Zardari's government, and specifically Taseer, for allowing Tuesday's shooting, saying the attackers had taken advantage of the political turmoil.
"The governor of Punjab is the most powerful person in the province and he was responsible for security, and security was weak, [so] I think he should resign. He is responsible for this huge lapse in security," Mir said.
"The governor was too busy infighting with Nawaz Sharif to take care of the security situation in Lahore."