By Omer Esiner of TravelexThe U.S. dollar rose to a new three-week high against a basket of major currencies overnight, benefiting from the broad pullback in investors' risk appetite and from the steep drop in commodity prices. Uncertainty about the outlook for indebted Greece ahead of an EU summit this week kept the single currency under pressure and dampened demand for riskier assets like stocks and emerging market currencies. Conflicting messages about financial assistance for Greece from various European leaders highlighted the lack of cohesion within the bloc and kept sovereign credit concerns squarely in the spotlight. Lack of support for Greece from the EU this week could prompt Athens to turn to the IMF, a development that could initially send the euro broadly lower. A surprise interest rate hike by India's central bank on Friday raised concerns that monetary tightening in Asia's third-largest economy may cool a key engine of global economic growth going forward. Commodities like crude oil and gold tumbled and investors pared exposure to dollar-bloc currencies from Australia, New Zealand and Canada. Commodity currencies remain vulnerable to further signs that key regional economies like India and China are taking steps to cool their red-hot economies, which could undermine some of their recent demand for resources. No U.S. or Canadian data is due out this morning. USD: The U.S. dollar firmed to a three-week trade-weighted high amid a backdrop of softer risk appetite and continued concerns about sovereign credit risk. India's surprise interest rate hike late last week dampened some demand for riskier assets like stocks and commodities and raised concerns that cooler regional growth could weaken an important engine of global recovery. The dollar also drew continued support from uncertainty about the outlook for Greece ahead of this week's summit of EU leaders. While U.S. economic data has recently painted a mixed picture of recovery in the world's largest economy, it was still generally consistent with the view that America's rebound will outpace most of its major rivals. With many forecasting a very strong rebound in jobs growth in next week's non-farm payrolls report, the risk remains to the upside for greenback going forward.