India's ruling Congress party has, however, put the blame squarely on Pakistan, saying it was the "epicentre and fountainhead of terror".
Relations between the two South Asian neighbours were already strained after India accused Pakistan of involvement in an attack on the city of Mumbai last November in which more than 170 people died.
'Declaration of war'
Gabol, who is a member of the ruling Pakistan People's Party, alleged the Lahore shooting was a direct response to that incident on November 26, during which 10 armed men targeted multiple locations across Mumbai.
"Every country in the world must unite against this scourge by isolating the country [Pakistan] and demanding immediate concrete results"
Indian Congress party spokesman
"This incident took place in reaction to 26/11," he said. "It is a declaration of open war on Pakistan by India."
Khaled Farooq, the chief of police in Pakistan's Punjab province, said the shooting in Lahore bore all the hallmarks of the Mumbai assault, which India says was was carried out by the Laskhar-e-Taiba group.
Burzine Waghner, a Pakistan analyst at the School of Oriental and African Studies in London, told Al Jazeera that the Indian intelligence agencies were unlikely to have been able to carry out such an attack.
"The terrorists that we saw on screen this morning seemed to be local," he said.
"The methods, including the asrsenal that they had; the magazines, the rocket-propelled launchers ... were very similar to what happened in Mumbai, an uncanny resemblance to say the least."
India, however, has said that the Lahore attack, carried out by 12 heavily armed men, highlighted Islamabad's failure to crack down on violent armed groups operating from its territory.
"They've got to address the problem, take courage in both hands, dismantle the infrastructure facilities available there," Pranab Mukherjee, India's foreign minister, said.
He warned of "a repetition of these types of incidents" if Pakistan did not deal with pro-Taliban fighters and other armed groups who have carried out hundreds of attacks on Pakistani targets.
'Epicentre of terror'
Abhishek Singhvi, the spokesman of India's Congress party, condemned Pakistan as "the epicentre and fountainhead of terror".
"Every country in the world must unite against this scourge by isolating the country and demanding immediate concrete results," he said.
Sri Lanka's cricketers were invited to tour Pakistan after the Indian national team pulled out of a planned Test series following the Mumbai attack.
Yusuf Raza Gilani, Pakistan's prime minister, told the Sri Lankan president that the Lahore attack was a "well planned conspiracy meant to create terror and isolate Pakistan's cricket".
Hasan Askar-Rizvi, a Lahore-based defence analyst, called the shooting a "daredevil, well-planned, and well-executed attack which shows the strength of terrorist forces in Pakistan".
"[It] shows the problems in the security system of Pakistan," he told Al Jazeera.
Pakistan is battling pro-Taliban and al-Qaeda fighters in the west of the country along the border with Afghanistan, as well as separatist groups in other areas of the country.
Hundreds of people were killed in violence across the country last year.
Sri Lanka has also seen attacks in the country's north and in the capital Colombo with government forces battling the rebel Liberation Tigers of Tamil Eelam (LTTE) with a view to end a decades-old 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.