Monday in southern San‘a began with the sound of machine-gun and artillery fire, as fighting broke out between Huthi "Popular Committee" militiamen and military units loyal to President Hadi. Some sources said the fighting started when Huthi fighters tried to set up a new checkpoint too close to the presidential palace. Others said the Presidential Guard began shelling a Huthi position unprovoked. Either way, the two sides exchanged fire for several hours, from about 6:00am until the late afternoon. President Hadi, who does not live at the presidential palace, was not in any direct danger during Monday's clashes. Minister of Information Nadia al-Sakkaf, who took control of the government's PR effort today, claimed that a "third party"--made up of forces loyal to former president 'Ali Saleh and his family--was also involved in the fighting today, and was responsible for shots that hit the prime minister's convoy and the vehicle of a Huthi representative as they left meetings with President Hadi. Notably, the Presidential Guard units fighting the Huthis did not appear to receive any support from other branches of the military during today's fighting.
By the afternoon, the fighting seemed to center on the hills overlooking the palace, known as al-Nahdayn, which are home to the 3rd Armored Brigade. Huthi officials claim that the Popular Committees took control of the base, which contains several tanks and armored vehicles, though government sources haven't confirmed this. The government did announce a ceasefire beginning at 4:30pm, and said that Huthi representatives were attending negotiations with the president, but sporadic fighting continued after that point. According to al-Sakkaf, the topics under negotiation include the release of Ahmad Awad bin Mubarak--the director of the office of the president, whom Huthi fighters kidnapped on Saturday--and changes to the new constitution, an advanced copy of which was released last week.
NOW: #houthis in meeting with president to agree on terms 4 releasing chiefof staff in return 4 changes in constitution & National Authority
— Nadia Sakkaf (@NadiaSakkaf) January 19, 2015
Despite early claims by many observers that San‘a was witnessing a coup d'etat, it's not clear what, if anything, was accomplished by Monday's fighting. At day's end, the AP reported that at least nine people had been killed in the fighting, and over 60 injured.
For a more detailed take, read this piece by Shuaib Almosawa and Kareem Fahim and this one from the AP. For a blow-by-blow account of the day's events, read through eye-witness Hisham al-Omeisy's Twitter feed.