Oil firms rise on uncertainty in talks to end war in Iran

** Shares of US oil and gas companies rise as oil prices climb

** Oil prices rose about 3% on Wednesday from the previous session's two-month lows, after Iran's security chief said Tehran would not allow even a single particle of enriched nuclear material to leave the country O/R

** Brent futures were up $2.77, or 3.03%, at $94.26 a barrel by 1531 GMT; US West Texas Intermediate crude gained $2.27, or 2.64%, to $88.31

** "While expectations of improving Middle Eastern supply availability and bearish US inventory data have weighed on the market, uncertainty around the US-Iran conflict continues to provide some support," ING analyst said in a note

** Oil major ExxonMobil XOM.N rises 1.3%, while Chevron CVX.N gains 0.85%

** SM Energy SM.N and Devon Energy DVN.N gains over 2% each

** Other producers APA APA.O, Occidental Petroleum OXY.N and EOG Resources EOG.N rise between 0.9% and 2%

** Refiner PBF Energy PBF.N rises about 4.7% and Valero Energy VLO.N gains 2.9%

** Oilfield services providers Baker Hughes BKR.O up 3.6%; while SLB SLB.N and Halliburton HAL.N rise 2.1% and 2.8%, respectively