Factions supporting and opposing President Ali Abdullah Saleh, who refused Sunday to sign the Gulf Cooperation Council deal to surrender power, blocked streets, the Yemen Observer reported.
"I went home and tried to arm myself by any means because I was afraid that if the president signs the initiative they will start looting and messing up the streets," said Mohammed Abdullah.
Bus passenger Salma Ahmad described a window-smashing attack by Saleh supporters as security forces stood by and did nothing.
Residents armed with guns and sticks guarded their neighborhoods against looters and many, especially women, stayed in their homes.
Yemeni aviation authorities closed Sanaa International Airport. Outgoing flights were suspended and incoming flights were diverted to other airports, China's state-run Xinhua news agency reported.
Citing an aviation official, Xinhua said the decision to close the airport was made "upon directions from the Yemeni political leadership."
At the offices of the government news agency Saba, journalist Farook al-Kamali was shot in the foot when tribesmen opposing Saleh attacked the building Monday, colleagues said.
Journalist Hassan al-Warith said Saba was bombarded with rocket-propelled grenades and other gunfire.
The attackers said the news agency and other government buildings were being used to attack the nearby compound of their tribal leader.