Gunmen have opened fire at a checkpoint outside the US embassy in Yemen's capital, Sanaa, Yemeni officials say.
They say three men carried out the attack in a car, and were later arrested. No injuries were reported.
Hours earlier, the US embassy said it had received a threat about a potential attack in "the foreseeable future".
US officials urged American nationals to exercise caution in the Arab country that has previously witnessed attacks by militants on Western interests.
"Gunmen in a car fired at the police in a neighbourhood close to the embassy," a security official told AFP news agency.
"Security forces chased them and managed to stop the car. Three gunmen who were in the car were arrested," he said.
Last September, at least 16 people were killed in a double car-bomb attack on the US embassy in Yemen, which Washington said bore all the hallmarks of al-Qaeda.
The militant organisation has long used Yemen as a haven and has often been blamed by the Yemeni government for attacks on Western targets in the country.