Oil prices rebounded this evening as traders watched the Iran crisis, and the weak US currency stimulated demand for dollar-priced crude.

US crude gained 83 cents to $68.33 a barrel, while London's Brent North Sea crude added 96 cents to $67.94.

Iran has ruled out cancelling its disputed presidential vote, issuing a new warning to the main opposition leader and lashing out at UN 'meddling'. The nation is the world's third biggest crude exporter after Russia and Saudi Arabia and produces approximately 3.8 million barrels of oil per day.

In foreign exchange activity, the European single currency climbed past $1.40 on better euro zone economic data ahead of this week's US Federal Reserve monetary policy meeting.

A struggling US currency makes dollar-priced oil cheaper for buyers holding stronger currencies, which tends to boost demand and lift prices.