HERAT, Afghanistan - At least three people were killed and 10 others injured early Friday morning when a blast and ensuing firing hit the US consulate in Herat city, the provincial capital of western Afghan province of Herat, a local security source said.

"Militants numbered three or four armed with heavy weapons and suicide vests stormed the consulate building at around 0515 local time. They tried to enter to the facility and take control of the building. Gunfight is still going on there," the source told Xinhua but declined to be named.

He said one attacker and two security guards were killed and seven civilian passers-by were wounded in the incident so far in the city 640 km west of Kabul.

The nature of the blast is said to be of the suicide nature, he noted.

"The number of the casualties might go up," he said. The blast also damaged the compound and several other nearby houses.  

No group has claimed responsibility for the incident at this moment of time.