The top heads of the state urged the public to preserve their peace and unite against the enemy in all forms.
The troops have been making gains against Al-Shabab in southern Somalia in the past few years.
A Houthi military spokesman had earlier said that air defenses had brought down a U.S. drone.
In 2013, he refused to swipe t-shirts with an Israeli player in a display of support for Palestinian rights.
The attack was the second in two days as the government tries to stabilize the country's capital.
The surprise decision gives the long-sitting assembly extra time to remain in power and serve.