Investigations are under way after a jack-up rig owned by Malaysia's Velesto Energy on Tuesday sunk offshore the state of Sarawak, East Malaysia.

Local media in Malaysia reported that the Naga-7, which was working for ConocoPhillips, had suffered a punch-through.

Malaysian drilling contractor Velesto confirmed the incident occurred “due to rapid penetration into the formation” on Monday. The jack-up Naga 7 tilted and subsequently on Tuesday “submerged at the location” - the Salam-3 appraisal well on Block WL4-00.