At least one company began evacuating non-essential personnel after a powerful 7.5 magnitude earthquake hit Papua New Guinea's energy-rich interior, causing landslides, damaging buildings and closing oil and gas operations.
The tremor hit in the rugged, heavily forested Southern Highlands about 560 km (350 miles) northwest of the capital, Port Moresby, at around 3.45 a.m. local time (1545 GMT Sunday), according to the U.S. Geological Survey (USGS).
A spokesman at Papua New Guinea's National Disaster Center said by telephone the affected area was very remote and the agency could not properly assess damage until communication was re-established.
He said there were no confirmed casualties, although the International Red Cross (IRC) in Papua New Guinea said some reports indicated there were "fears of human casualties".
"It's a very serious all across the Southern Highlands and also all over the western highlands. People are definitely very frightened," Udaya Regmi, the head of the IRC in Papua New Guinea, said by telephone from Port Moresby.
The PNG government also said it had sent disaster assessment teams. At least 13 aftershocks with a magnitude of 5.0 or more rattled the area throughout the day, according to USGS data, but no tsunami warnings were issued.
"The Papua New Guinea Defense Force has also been mobilized to assist with the assessment and the delivery of assistance to affected people as well as the restoration of services and infrastructure," Isaac Lupari, the chief secretary to the government, said in a statement.
ExxonMobil said it had shut its Hides gas conditioning plant and that it believed administration buildings, living quarters and a mess hall had been damaged. It also said it had suspended flights into the nearby Komo airfield until the runway could be surveyed.
"Due to the damage to the Hides camp quarters and continuing aftershocks, ExxonMobil PNG is putting plans in place to evacuate non-essential staff," the company said in an emailed statement.
Gas is processed at Hides and transported along a 700 km (435 miles) line that feeds a liquefied natural gas plant near Port Moresby for shipping.