The G20 finance ministers and central bankers meeting will be in session starting Friday.

Prior to Thursday's opening, the People's Bank of China set the midpoint rate of the yuan at 6.6872 per US dollar, 0.11 percent firmer than the previous fix.

The spot yuan opened at 6.6818 per dollar, and closed at 6.6783 per dollar, 3 points lower than the close in previous day. In mid day trading, the yuan once rose to lower than 6.67 per dollar.

Earlier in the week, the yuan fell through the psychologically important 6.7 level on Monday.