Oil back up to $100 a barrel on Thursday

U.S. crude traded up $2.62 to $98.78 a barrel by 1205 GMT after touching a high of $100.10 earlier, adding to a $6 gain on Wednesday. London Brent crude rose $2.51 to $97.35 a barrel.

The strife on financial markets this week had pushed crude down 10 percent on Monday and Tuesday as investors fled oil for saver havens.

The world's top central banks announced on Thursday they will pump more than $180 billion in extra dollar funds into global money markets in a coordinated effort to ease the growing funding squeeze -- driving up global stocks and bolstering oil.

"Most of the big moves at the moment are financial market related rather than related to the fundamentals. A bit of weakness in the dollar seems to have pushed prices higher right now," said Tony Machacek, broker at Bache Commodities.

Investors had flocked into oil and other commodities earlier this year as a hedge against the weak dollar, sending crude to a peak over $147 in July before slowing demand in the United States and other consumer nations sent prices tumbling.

Gold prices have rallied almost 12 percent over the last-two days, as investors look for a safe-haven away from rattled equity and bond markets.

Hurricane Ike toppled several platforms in the Gulf of Mexico and 12 refineries along the Gulf Coast remain shut following the storm.

Nearly 96 percent of oil production in the Gulf -- home to a quarter of U.S. output -- was still offline on Tuesday while a U.S. government

report released on Wednesday showed a sharp drop in crude stocks in the world's top consumer.

Rising tensions in Nigeria's crude rich Niger Delta region have heightened supply concerns, with militants threatening on Wednesday to broaden their "oil war" to offshore oilfields.

The Movement for the Emancipation of the Niger Delta has cut a fifth of OPEC member Nigeria's oil output.