Energy markets were on edge on Monday, waiting for Russia to invade Ukraine or to back off its threats. The stakes are high because Russia is Europe’s primary source of natural gas and supplier of roughly one of every 10 barrels of oil the world consumes.

The uncertainty was reflected in European stock indexes. The Stoxx Europe 600 was 2.5 per cent lower, and Germany’s DAX dropped 3.2 per cent. On Wall Street, futures for the S&P 500 pointed to a drop of about 1 per cent when trading starts.

Oil prices have risen to well over $90 a barrel in recent days as Russian troops massed along Ukraine’s borders, and many experts say an outright invasion would send the price above $100 a barrel. The average price for regular petrol in the US has risen to nearly $3.50, a rise of almost 20 cents over the last month.