Bahrain on Saturday asked citizens to leave Iran and Iraq and Exxon Mobil evacuated foreign staff from a southern Iraqi oilfield amid heightened fears of attacks by Iran or allied forces in the region.
Bahrain's foreign ministry also warned against travel to Iran and Iraq, citing “the unstable situation in the region and the recent escalations and threats against security and stability”, in a statement released through the Bahrain News Agency.
The warning comes days after drone attacks on Saudi oil pumping stations that Saudi Arabia blamed on Iran-backed rebels in neighbouring Yemen, and in the same week that four oil tankers were sabotaged off the UAE's Fujairah coast.
The incidents added to already heightened tensions in the region following the tightening of US sanctions on Iran, particularly its vital oil exports, and the deployment of US warships and bombers to the Arabian Gulf to deter what White House officials said was a "credible threat" of attacks on its interests by Iran or its proxies.
Exxon operates in Iraq's Basra province where a rocket was fired at the US consulate in September in an attack blamed on Iran-backed Shiite militias. The head of Iraq's South Oil Company, Ihsan Abdul Jabbar, said the evacuation was a "precautionary and temporary measure".
The attacks on the oil tankers is still being investigated by UAE, Saudi Arabia and Norway, under whose flag one of the vessels was sailing, but a confidential assessment by a Norwegian insurer has concluded that they were "highly likely" to have been facilitated by Iran's elite Islamic Revolutionary Guard Corps.
The report, seen by Reuters, said the attack was likely to have been carried out by a surface vessel operating close by that dispatched underwater drones carrying 30-50 kilos of high-grade explosive to detonate on impact. Its conclusion was based in part on a similarity in the shrapnel found on the Norwegian tanker to shrapnel from drone boats used by Houthi rebels off the coast of Yemen.
Besides the Houthi rebels and militias in Iraq, Iran's proxies in the region include the Hezbollah movement in Lebanon and various armed groups supporting the Assad regime in Syria. The US on Wednesday pulled non-emergency staff members from its embassy in the Iraqi capital Baghdad out of apparent concern about perceived threats from Iran, while Germany and the Netherlands suspended training missions in Iraq by forces that are part of the international coalition to defeat ISIS.
The US and Iran have both said they are not seeking a military confrontation but the heightened tension has raised the possibility of accidental attacks.
On Saturday, the US diplomatic missions in the UAE and Kuwait relayed a warning from the Federal Aviation Authority that commercial airliners flying over the Gulf risked being targeted as result of "miscalculation or misidentification".
The FAA Notice to Airmen said that all commercial aircraft flying over the waters of Arabian Gulf and the Gulf of Oman needed to be aware of "heightened military activities and increased political tensions in the region" that posed "an increasing inadvertent risk to US civil aviation operations".
It also said aircraft flying through these areas could experience "inadvertent GPS interference and other communications jamming with little to no warning".
UAE carriers Emirates Arline and Etihad Airways said they were aware of the notice and their operations were unaffected. Oman Air did not respond to a request for comment.