"Our focus is... with respect to options in Syria, in the diplomatic and financial space at the moment," said Jacob Sullivan, director for strategic policy and a close advisor to Secretary of State Hillary Clinton.

The United States on Monday said it was considering targeted sanctions against senior Syrian officials, and announced it was withdrawing diplomats' families and non-essential embassy personnel from Damascus.

"At the moment, we're not actively considering shutting down our embassy in Syria," said Sullivan. "We believe that our diplomatic lines of communication there offer an opportunity to communicate directly with the Syrian government in ways that we would like to continue to do."

Sullivan reiterated that the United States condemns the repression in Syria, saying the actions taken by President Bashar al-Assad "are totally unacceptable" and "completely inconsistent" with those of a responsible leader.

The post of US ambassador to Syria was filled in January after being vacant for six years.

Several European leaders also sharpened their comments on Syria Tuesday after the Syrian army opened fire once again on inhabitants of Daraa, a focus of the protests south of Damascus.