As some of his closest military and tribal allies abandoned him, Saleh refused to submit to calls for his resignation and claimed he had the support of the vast majority of people in the impoverished Arabian Peninsula country.

"We're still here... the great majority of the Yemeni people are with security, stability and constitutional law," he said. "Those who are calling for chaos, violence, hate and sabotage are only a tiny minority."

Tanks took up position in key locations across Sanaa including at the presidential palace, the central bank and the defence ministry, but it was unclear what their orders were or who was in charge.

A statement from the country's military command late Monday said it remained loyal to Saleh and would not allow "any attack on democracy and the constitutional order."

AFP