Oil extended its decline after its biggest weekly drop since March as investors weighed the prospects of Iran increasing crude exports in an oversupplied market.

Futures dropped as much as 1.8 percent in New York after capping a 7.4 percent loss through July 10. Iran and world powers may announce a nuclear deal as soon as Monday after a political agreement was reached to lift a United Nations arms embargo. Prices also slid as investors eschewed risky assets amid concern Greece may be cut from the euro area.

Oil rebound from a six-year low has faltered, capping a second weekly drop on Friday, as a rout in Chinese equities and the turmoil in Greece stoke speculation demand will weaken and a global glut will persist. Prices may fall further as the world remains “massively oversupplied,” before markets tighten in 2016 when output growth outside OPEC grinds to a halt, according to the International Energy Agency.

West Texas Intermediate for August delivery lost as much as 97 cents to $51.77 a barrel in electronic trading on the New York Mercantile Exchange and was at $52.10 a barrel at 10:36 a.m. Sydney time. The contract fell 4 cents to $52.74 on Friday. Prices have decreased 2.2 percent this year.

Brent for August settlement slid as much as 92 cents, or 1.6 percent, to $57.81 a barrel on the London-based ICE Futures Europe exchange. Prices fell 2.6 percent last week. The European benchmark crude was at a premium of $5.91 to WTI.

Source : Bloomberg