Heavy Arab raids rock capital city

UN, Red Cross alarmed over casualties in airstrikes; Iran denies military aid to Houthis

Explosions lit up the sky above Yemen's capital as Arab coalition warplanes pounded rebel positions in the heaviest raids yet of the 6-day-old Saudi-led operation, witnesses said on Tuesday.

Huge blasts were heard overnight in Sanaa when coalition forces hit a missile depot belonging to the renegade Republican Guard, which is loyal to former strongman Ali Abdullah Saleh.