"In the current situation it clearly is a very dangerous place," David Morgan, president of the International Cricket Council, told BBC television after the deadly attacks on Sri Lanka's cricket team in the Pakistani city.
Asked about plans for the World Cup, due to be played in four Indian subcontinent countries, Morgan said: "Things will have to change dramatically in Pakistan in my opinion if any of the games are to be staged there."
"I think that international cricket in Pakistan is out of the question until there is a very significant change, a regime change I guess," he added.
An ICC spokesman said he assumed Morgan was referring to a call by Pakistani senators this week for the Pakistani cricket board to be sacked.
In an interview with BBC radio, Morgan added: "Quite clearly there could be a regime change in Pakistan and the place could become safe and peaceful again, but that all remains to be seen...
"The World Cup was awarded to the four countries in the Indian subcontinent. The allocation of matches between those four countries is yet to be made.
"Quite clearly, this event puts a great question mark over the ability of Pakistan to host cricket world cup matches."
Eight people died when the Sri Lankan cricket team's convoy was attacked by masked gunmen as they travelled to play at the Gaddafi stadium in Lahore. Seven team members were injured.
Pakistan's High Commissioner to Britain Wajid Hasan meanwhile told Sky News television that it was too early to talk of the end of international cricket in his country.
"I wouldn't like to rush to that sort of conclusion," he said.