Colombo, Aug 16 : Sri Lankan President Ranil Wickremesinghe has instructed heads of all government institutions to adhere to a circular issued by the Treasury on the limits of government expenditure. In a statement issued on Monday, the President's media unit said that the heads of the institutions exceeding these limits will have to use their personal funds to finance the expenses, Xinhua news agency reported. The media unit said these instructions have been relayed to the ministry secretaries, heads of departments, provincial secretaries, corporation presidents, institutional boards and government-owned trading institutions. The government decided to limit expenses of state institutions to help overcome the economic challenges facing the country, the media unit said. President Wickremesinghe advised heads of institutions not to lease new buildings, and the approval of the Treasury is needed before renting new vehicles or extending existing lease agreements. /IANS