Shia militiamen stormed the Yemeni presidential complex in the capital Sanaa on Tuesday and heavy clashes broke out inside.
The Huthi militia fighters also clashed with troops protecting the residence of President Abdrabuh Mansur Hadi in another part of the city, according to witnesses.
Yemen has been wracked by unrest for months, raising fears of a collapse of Hadi’s government, a crucial ally in Washington’s fight against al Qaeda.
The Huthis overran Sanaa unopposed in September after sweeping down from their northern stronghold, but the presidential complex in the south of the capital had remained outside their control.
Tensions have been running high since the Huthis abducted Hadi’s chief of staff, Ahmed Awad bin Mubarak, on Saturday.
The fighting near Hadi’s residence in western Sanaa broke out when Huthis attempted to set up a new checkpoint nearby and were confronted by troops, witnesses said.