Pakistan Prime Minister Nawaz Sharif said Saturday that a general election would not be held in the country before 2018.He thus rejected the demands by the opposition Pakistan Tehreek-i-Insaf (PTI) for early elections, a Dawn online report said.The PTI has been holding countrywide demonstrations in protest of the government's alleged corruption and rigging in the 2013 general election. The opposition party has been demanding that Sharif should step down as the country's prime minister, paving way for an 'independent inquiry' into the alleged electoral rigging.Sharif's statement comes as the PTI gears up to hold what it promises would be a landmark rally in Islamabad Nov 30.In an official statement, Sharif said that all political forces have stakes in the democratic system.“No system is perfect, but the constitution and parliamentary democracy are the only tools to remove the imperfections in the existing system,” Sharif said.He said that his party would have achieved a prospering Pakistan when it enters election mode in 2018.