Blast heard near security building in Yemeni capital - residents
Following the explosion sirens were heard, in a warning to people in the area not to leave their homes, the residents said.
The cause of the explosion was not clear, but earlier, in another district in Sanaa, residents said they had heard an exchange of gunfire between militants and Security (SECURITY.8)personnel at the presidential palace.
(Reporting by Mohamed Ghobari; Writing by Amena Bakr; Editing by William Maclean and Robin Pomeroy)