U.S. oil price slipped below 100 dollars a barrel on Friday as Saudi Arabia added supply and the dollar gained strength.
According to industry sources on Friday, Saudi Arabia was offering more crude oil to Asian refiners for July after it failed to persuade the OPEC to raise output. More supplies helped pull down the crude prices, which were accused of being the main reason of global inflation.
And the crude pricing currency, the greenback, gained as the euro weakened amid concerns about Greece's debt problem. The dollar index rose nearly 1 percent, making oil much more expensive for investors holding foreign currencies.
Besides, China's export for May fell sharply by more than 10 percent, resulting in a smaller-than-expected trade surplus and making investors pessimistic about the oil demand.
Light, sweet crude for July delivery fell 2.64 dollars, or 2.59 percent, to settle at 99.29 dollars a barrel on the New York Mercantile Exchange. For the week, it dipped 93 cents, or 0.93 percent.
In London, Brent crude for July delivery dropped 79 cents, or 0. 66 percent, to close at 118.78 dollars a barrel, posting a weekly gain of 2.94 dollars or 2.54 percent.
