HONG KONG (AFP) - Asian investors ended a tumultuous week on a cautious note Friday as the prospect of a debilitating global trade war hung over regional markets. As European Union tariffs on key US goods -- including jeans, bourbon and motorcycles -- came into effect, there were fears China and the US will carry through with their own threats, locking the world’s three biggest economies in a potentially destructive face-off. The EU move was in retaliation to Donald Trump’s decision to hit steel and aluminium imports from the bloc, and comes after the US and China traded tit-for-tat threats on hundreds of billions of dollars of goods. That exchange sparked an international market retreat and fuelled worries a full-blown flare up could pummel the global economy just as it is getting back on its feet after the global financial crisis. "We have a trade war -- and it’s an escalating trade war," SEB chief economist Robert Bergqvist told AFP in an interview. "Investors... are more cautious today, they are waiting for the right time to reduce their exposure in stock markets." New York’s three main indexes ended down -- with the Dow suffering an eighth straight loss -- as investors were spooked by news that Daimler had cut its profit forecasts because of new levies on cars exported from the US to China. "We heard from Daimler about the impact of the trade tensions on sales, and there are a growing number of stories about the chance of China directly targeting US firms who do business in the country," said Greg McKenna, chief market strategist at AxiTrader. "What comes to pass is still uncertain in that regard. What’s not uncertain, though, is the resolve of US Commerce Secretary Wilbur Ross to pursue China and try to change it -- and other nations’ -- actions."