The Friday deaths of more than 50 demonstrators in Sanaa sparked a wave of defections from top Yemeni generals and officials, including many of the country's foreign diplomats.
Yemeni President Ali Abdullah Saleh told his remaining military leaders that any effort to seize control of the country in a coup would lead to civil war, the country's official Saba news agency reports.
"There is a constitution, laws, regulations and people's will, and a minority cannot control the fate of the nation," he was quoted as saying.
The opposition movement in Yemen rejected an offer by the president to step down in early 2012, instead calling for his immediate resignation, officials told CNN International. Saleh promised initially to end his 32-year rule in 2013 and previously expressed intentions to reach out to the opposition.
Yemen is a key ally in the U.S. fight against al-Qaida. U.S. Defense Secretary Robert Gates was quoted by CNN as saying instability in Yemen was an obvious concern for Washington.
"We consider al-Qaida in the Arabian Peninsula, which is largely located in Yemen, to be perhaps the most dangerous of all the franchises of al-Qaida right now," he added.
Apart from AQAP, Saleh is facing a Shiite insurgency in the north of the country and a violent secessionist movement in the south.