Indonesia yesterday said it would seize Asia's largest undeveloped gas block from ExxonMobil and ask Pertamina, the state-owned energy group, to prepare a feasibility study to take over the field. The latest move in a three-year dispute between Jakarta and the US energy group was made after talks with Exxon about the Natuna D-Alpha field became deadlocked over tax issues, the extension of a contract and how to split the gas, said Purnomo Yus-giantoro, Indonesia's energy minister. Natuna is one of the biggest investments in the oil and gas sector in Indonesia, which desperately needs foreign investment to reduce unemployment levels and spur economic growth. The block, which accounts for about a quarter of Indonesia's recoverable gas reserves, is estimated to need investment of about $30bn (