Dozens more were wounded after police fired live rounds at protesters on Tuesday.
The Shia activists have been camped out in the capital for weeks in a campaign to bring down the government and reverse unpopular fuel price increases.
Houthi activists have been holding daily rallies in Sana’a and Sa'ada, with tens of thousands taking part.
They accuse the government of corruption and marginalizing the Shia community.
Hadi’s government has offered to reverse a decision to cut fuel subsidies and form a new government in the Arab country, but Houthis insist that the government should resign.
According to a source close to the presidency, the Houthis have submitted a list of demands, including “uprooting corruption” as well as “giving them more powers within the public prosecution, accountability panel, national security services and the intelligence” services.
They also want Hadi to “consult with them on naming the new prime minister” and the ministers of defense, interior, foreign affairs and finance.
On Sunday, Yemeni police’s special forces killed one protester and injured around 40 others as they attacked them to disperse a Houthi sit-in blocking the road to Sana’a airport.
BA/BA