The economy still faces downward pressure and domestic and external situations are "grim" as industrial output posted its slowest growth in nearly three years, the Ministry of Industry and Information Technology warned on Wednesday.

Difficulties faced by companies and the consequences of sustained "sluggish" external demand should not be underestimated, Zhu Hongren, the ministry's chief engineer, said.

Industrial output grew by 11.6 percent year-on-year in the first quarter of 2012, the slowest growth since July 2009, according to figures released by the National Bureau of Statistics.