Asian shares fell to two-month lows on Thursday, and the US dollar rose as talks about raising the US debt ceiling remained inconclusive. With no resolution in sight, traders were wary of a possible US government default that could lead to detrimental impacts on the global economy. Credit ratings agencies also put the US on watch for a possible downgrade, thereby adding to the dampened investor sentiment. While Wall Street's main indexes closed lower overnight on debt-ceiling concerns, Nasdaq futures rose 1.4% higher after Nvidia's forecast for second-quarter revenue.