Oil fell again Monday after its first monthly decline since May as a deepening trade war further stoked fears that fading global economic growth will hurt fuel demand.

Futures dropped to trade near $55 a barrel in New York, having lost 5.9% in August. U.S. tariffs on a further $110 billion of Chinese imports took effect on Sunday, and additional Chinese levies on American products -- including oil for the first time -- also kicked in.

West Texas Intermediate for October delivery fell 7 cents to $55.03 a barrel on the New York Mercantile Exchange as of 8:57 a.m. local time after falling as much as 1.1% earlier. The contract lost $3.48 in August.

Brent for November settlement slid 23 cents to $59.02 a barrel on the ICE Futures Europe Exchange, and traded at a $4.21 premium to WTI for the same month. The October contract expired on Friday, having lost 7.3% last month.

Source : Bloomberg