The Yemeni Army and the defected army clashed in Sanaa, Al Jazeera reported.
The fighting aircrafts were also involved in the clashes. The air strikes on defected First Armored Division killed two people and injured ten.
Meanwhile, the security forces killed 20 protestors, including a child, near the central square in Sanaa.
Since February, millions of Yemenis have been demanding the ouster of Ali Abdullah Saleh, who has been in power for 32 years. Yemeni security forces use their weapons to disperse the anti-government actions. According to Western media, for two months the popular unrests in the country killed several hundreds people.
Despite months of protests, Saleh, who has been receiving treatment in neighbouring Saudi Arabia for the past three months for blast wounds he sustained in a bombing at the presidential palace, has so far refused to hand power to his deputy.
The UN plans also calls for the immediate launch of negotiations on the formation of a government of national reconciliation, which would rule the country for an interim period of three or six months during which preparations would be made for a presidential election.