China signed two multibillion, dollar long-term deals to buy liquefied natural gas from Qatar on Thursday, marking a milestone in Asia’s evolution as the hottest market for the fuel.

PetroChina struck a deal to buy 3m tonnes of LNG a year over 25 years from 2011 with Qatar and Royal Dutch Shell, its partner. Analysts said the deal could could be worth as much as $60bn (£30.4bn).