[Updated at 11:44 a.m. ET] Egypt's highest court declared the parliament invalid Thursday, and the country's interim military rulers promptly declared full legislative authority, triggering a new level of chaos and confusion in the country's leadership.

The Supreme Constitutional Court also ruled that a former member of President Hosni Mubarak's regime may run in a presidential election runoff this weekend.

The ruling on parliament means that it must be dissolved, state TV reported.

The court found that all articles making up the law that regulated parliamentary elections are invalid, said Showee Elsayed, a constitutional lawyer.

Parliament had been in session for just over four months. It was dominated by Islamists, a group long viewed with suspicion by the military.

The Supreme Council of the Armed Forces, in control of the country since Mubarak's ouster, announced that it now has full legislative power and will announce a 100-person assembly that will write the country's new constitution. The court's rulings come a day after Egypt's military-led government imposed a de facto martial law, extending the arrest powers of security forces.