The Asian Development Bank expects slower growth than expected for developing nations on the continent this year and next, it said in a report Wednesday, citing weakening domestic investment due to external factors such as the U.S.-China trade war for its 5.2 percent expansion forecast.

In its Asian Development Outlook Supplement, the Manila-based bank revised its initial growth forecast of 5.7 percent for 2019 and 5.6 percent for 2020, which it subsequently trimmed down last September to 5.4 percent and 5.5 percent, respectively, for developing Asia, an ADB region that groups 45 member economies that include China and India but not Japan.

"Prolonged trade tensions still comprise the primary risk to the outlook," the report said, also citing factors such as slowing global trade and economic activity, and a global downturn in electronics.