Security is tight near the United Nations building in the Yemeni capital Sanaa. The UN closed its offices after reports of potential car bombs in the city.
Police troops in Yemeni capital Sanaa have been on high alert since an attack last week on the Yemeni Defence Ministry compound.
Disturbing CCTV footage has been released of the assault in which 52 people were killed and 167 injured.
The dramatic images show a suicide bomber and gunmen attacking a hospital inside the compound on the morning of December 5 as ministry staff were arriving for work.
The suicide bomber can be seen driving a car packed with explosives into the gate of the compound, followed by a huge burst of flames. Gunmen in another vehicle sped in and opened fire on soldiers, doctors and nurses working at the hospital.
The footage also shows an attacker arming a grenade’s fuse then lobbing it into a group of workers before running away. The grenade can be seen exploding.
The US military raised its alert status in the region after the coordinated strikes. Yemen is home to what Washington has called the main stronghold of al-Qaeda in the Arabian Peninsula (AQAP).
Meanwhile, 15 people on their way to a wedding in Yemen were killed in an air strike after their party was mistaken for an AQAP convoy, according to local security officials.
One security official said: “An air strike missed its target and hit a wedding car convoy, ten people were killed immediately and another five who were injured died after being admitted to the hospital.”
Yemen is among a handful of countries where the US acknowledges using drones, although it does not comment on the practice.
Human Rights Watch said in a detailed report in August that US missile strikes, including armed drone attacks, had killed dozens of civilians in Yemen.