Oil prices neared $105 today after the resignation of Portuguese Prime Minister Jose Socrates renewed euro-zone concerns.

US benchmark West Texas Intermediate fell 22¢ to stand at $105.53 and May Brent dropped 49¢ to $115.06 a barrel, reports Reuters.

The resignation of Socrates is expected to increase the likelihood of Portugal joining Greece and Ireland for an EU bailout, which will also put pressure on the euro.

Investors also continue to focus on unrest across the Middle East and North Africa, which led WTI crude to its highest settlement since 2008 on Wednesday, with help from a larger-than-expected fall in US petrol inventories the previous week.