Fighting between Shia rebels and Sunni militias in Yemen has escalated, with clashes on the edge of the capital.
Armed rebels, known as Houthis, shelled buildings of the state TV and the main Sunni Islamist party, Islah, in Sanaa.
Hundreds of residents have fled their homes and international flights to the city have been suspended.
About 40 people have been killed since Tuesday, reports say. The rebels have staged protests for weeks, demanding political and economic reforms.
President Abdrabbuh Mansour Hadi has dismissed the government and promised to review a decision to cut fuel subsidies.
Over the past few weeks the rebels have occupied protest camps on the road to the airport and staged sit-ins at ministry buildings, as well as clashed with fighters loyal to Islah.
On Thursday night Houthi fighters attacked the state television headquarters in Sanaa.
"The Houthi group is continuing to shell the television building with all kinds of weapons until this moment," the channel said on Friday morning.
As fighting intensified, foreign airlines suspended flights to the Sanaa.
"Arab and foreign airlines have decided to suspend their flights to Sanaa for 24 hours because of developments in the capital," the Civil Aviation Authority said in a statement on state news agency Saba.
The measures could be extended depending on the security situation, the statement added.