An over-speeding car with three drivers appeared not to stop for inspection and then police fired two warning shots in the air to force the drivers to lower speed, the source said.

The car has been seized along with the drivers.

There was not an exchange of fire and the drivers shot neither police nor the US embassy in the area, the source affirmed.

The embassy compound is far from the checkpoint, the source added.

Initial investigations with the drivers revealed they had no weapons, the source said, pointing out that if the drivers could face charges they will be over high speed only.

Earlier reports said that a fire exchange took place near the US embassy between troops and gunmen.

The reports come hours after the US embassy in the capital Sana’a said released warnings for the US citizens in Yemen based on Al-Qaeda threats of possible attacks on US targets in the country.

The warnings urged the US citizens to be cautious and avoid crowed areas and places famous for westerners.