The resignation of US Secretary of Defense James Mattis has added to political turbulence in Washington (AFP Photo/Brendan Smialowski) European stocks extended losses Friday and oil prices struck multi-month lows as political turbulence in Washington, renewed fears over US-China relations and economic growth strains weighed on markets. "Stocks are... in the red, with the risk of a US government shutdown taking the blame," said Joshua Mahony, market analyst at IG trading group.