Time : ` ` The situation is tense , '' a Yemeni security official said . It is not clear what set off the explosion . The airport and air base were shelled by rebels , '' said the official , who was not authorized to speak to the media . There are no immediate reports of casualties . Trains to Sanaa are being diverted to Aden .
Time : ` ` The situation is tense , '' a Yemeni security official said . It is not clear what set off the explosion . There are no immediate reports of casualties . Trains to Sanaa are being diverted to Aden .