Rebel Shiite Houthis battled soldiers near Yemen’s presidential palace and elsewhere across the capital Monday, seizing control of the country’s state-run media in a move an official called “a step toward a coup.”

The fighting near the palace marks the biggest challenge yet to the government of President Abed Rabbo Mansour Hadi. The battles saw the convoys of Yemen’s prime minister and a top presidential adviser affiliated with the Houthis come under fire, as well as Houthi fighters take over Yemen state television and its official SABA news agency, Information Minister Nadia Sakkaf said.

“This is a step toward a coup and it is targeting the state’s legitimacy,” Sakkaf told The Associated Press.