WASHINGTON: US consumer prices rose less than expected in March and underlying inflation slowed, suggesting the Federal Reserve will remain cautious about raising interest rates this year. Other data on Thursday showed the number of Americans filing for unemployment benefits fell last week, revisiting a level last seen in 1973, showing sustained strength in the labour market. Labour Department said its Consumer Price Index (CPI) gained 0.1 per cent last month as a rebound in gasoline prices was partly offset by a drop in cost of food. There were also slow-downs in medical care and housing costs.