GENEVA, Sept. 27 (Xinhua) -- The World Trade Organization (WTO) on Thursday revised downward its forecast for global merchandise trade growth both in 2018 and 2019, citing escalating trade tensions and tighter credit market conditions in important markets.

The WTO adjusted its forecast for the 2018 world trade volume growth to 3.9 percent, lower than 4.4 percent previously forecast in April.

Meanwhile, it also downgraded its outlook for 2019 to 3.7 percent from its previous forecast of 4.0 percent.

The WTO estimated that trade will continue to expand but at a more moderate pace than previously forecast.

"Rising trade tensions pose the biggest risk to the forecast, but monetary policy tightening and associated financial volatility could also destabilize trade and output," explained the WTO.

The latest statistics shows that North America had the fastest export growth and Asia had the strongest import growth in the first half of 2018 while resource-based economies still struggled.