The Bank of Japan voted unanimously Friday to keep its key interest rate unchanged at zero to 0.1 per cent in a widely expected move aimed at propping up the economy, according to dpa. "Japan's economic activity has started picking up moderately as domestic demand remains firm mainly supported by reconstruction-related demand" after last year's earthquake and tsunami that struck north-eastern Japan, the central bank said in a statement. Last week, the government said the nation's economy grew at an annualized rate of 4.7 per cent in the January-March quarter, beating earlier estimates, on the back of stronger-than-expected domestic consumption. However, the bank said the economy still "faces the critical challenge of overcoming deflation and returning to a sustainable growth path with price stability."