The US embassy in Damascus is closing for one day on Thursday for security reasons, according to the embassy's website.
Several Syrian organizations protested in the streets against a US raid on Sunday inside Syrian territory, in which the US said it targeted an al-Qaeda leader. Syria says eight civilians were killed, reported dpa.
Protestors chanted national slogans and carried pictures of the Syrian President Bashar al-Assad.
So far the US government has not given an official clarification of the attack.