Oil prices rise after kidnappings

Fears over supplies are increasing

Oil rose by nearly two dollars a barrel after eight Western workers were kidnapped in Nigeria, and US-Iran tensions increased.

Light crude rose by $1.99 on Friday, sticking at $72.33, while Brent crude climbed by $1.64, settling at $71.03.

"The geopolitical risks are on the supply side. Security is worsening in Nigeria and Iraq," said Deborah White of SG CIB.

The rise came a day after Opec voted to leave oil output quotas the same.

Attacks on oil rigs operated by foreign firms in Nigeria have intensified in recent months, reducing the country's oil production by 25%.

The latest rig to be attacked in Nigeria is owned by Norwegian firm Fred Olsen Energy.

Meanwhile tensions between the US and Iran increased on Friday as Iranian President Mahmoud Ahmadinejad said his country would not surrender its right to develop nuclear technology, following Western pressure to do so, local media reported.

There are fears that if the US decided to apply sanctions to Iran, this would hamper oil supply, analysts say.

US holiday season

Such supply concerns are compounded as the so-called driving season in the US gets under way, during which time Americans use their cars more than usual for holiday purposes.

Figures released Thursday revealed that US petrol inventories were lower than expected.

Lower production at two Texan refineries also fuelled worries.

"Any refinery problems will cause the market to rally, as we are going into big demand season," said Tony Nunan, risk manager at Mitsubishi.