Hong Kong stocks reversed gains to end lower on Friday, as investors worried about heightening geopolitical tensions in the Middle East after a US air strike at Baghdad airport killed a top Iranian commander.

But stocks on the island managed to the wrap up the first week of the new decade higher with a five-week winning streak, thanks to an accommodative stance by China's central bank and a thaw in Sino-US trade tensions.

The Hang Seng index fell 0.3%, to 28,451.50, after climbing as much as 1.2% to a six-month high, while the China Enterprises Index lost 0.6%, to 11,253.55.

For the week, HSI increased 0.8%, while HSCE moved up 0.5%, both up for the past five weeks in a row.

The benchmark Hang Seng index had advanced 7% in the last month of 2019 amid signs of progress in Sino-US trade talks. Investors were expecting a signing of a Phase 1 trade deal between China and the US on Jan. 15.