LONDON, Feb 15 (Reuters) - U.S. Treasuries firmed in Europe on Friday after strong demand at a 30-year bond auction and renewed concerns about the weakness of the euro zone economy increased demand for low-risk assets. The U.S. government sold $16 billion of 30-year bonds at a high yield of 3.180 percent on Thursday, drawing solid demand and sparking a rally in U.S. paper. The auction wraps up a busy week in terms of supply, with debt sales totalling $72 billion. Ultra-long bonds outperformed the rest of the curve on Friday, with the 30-year yield dropping 2.7 basis points to 3.1509 percent, while the benchmark 10-year T-note yield dipped 1.4 bps to 1.9844 percent. T-note yields hit 10-month highs of 2.062 percent earlier this week. "Supply was a concern this week, but now that it is behind us, bonds look in pretty okay shape," said Craig Collins, a trader at Bank of Montreal. He expected yields to continue falling near-term towards 1.9250, around February's lows. Traders said data showing the euro zone economy sliding further than expected into recession was also giving Treasuries a lift. Worries about the region's economy may increase if the euro currency continues to appreciate, hurting exporters' competitiveness. Talk of "currency wars" will feature high on the agenda of a Group of 20 meeting in Moscow. Hosts Russia say the G20 will back the thrust of a G7 text, which reaffirmed a commitment to floating exchange rates.