Concerns over Iraq have also been mounting.
Amrita Sen, chief oil analyst at Energy Aspects, told the BBC: "We do not expect southern Iraqi oil exports [which account for the bulk of Iraqi exports] to be impacted by the current conflict, as the fields remain far away from where the fighting is currently ongoing.
"In the highly unlikely and very small probability that southern exports do get impacted, oil prices are likely to rise sharply, possibly towards $130 or higher, as it will not be possible for the world to replace Iraqi production, simply because the world doesn't have that much spare capacity available.